Total mass in LEO is just under 300 tons, of which 175 tons is cryogenic fuel. The storable fuel is 53 tons, and the payload 72 tons. So four Jupiter 232 launches or about 12 EELV launches, plus an Orion crew module (and another one to collect – or can it stay in orbit for 18 months.{snip}
Any chance of launching this mission whilst Obama is still president, i.e. in the next 7 years?
Quote from: A_M_Swallow on 09/19/2009 11:59 pmAny chance of launching this mission whilst Obama is still president, i.e. in the next 7 years?Not likely for two reasons. The first is to get a political agreement to do it in time isn't likely. The second and bigger reason is that there is no good solution to bone loss as of yet. The demineralization numbers for long duration flight are just plain scary. What good would it do to send a crew where some members just might not survive the return to Earth.
The second and bigger reason is that there is no good solution to bone loss as of yet. The demineralization numbers for long duration flight are just plain scary.
Alex.Do we know anything certain about the resources available on Phobos for ISRU ?Nick.
Quote from: Eric Hedman on 09/20/2009 01:29 amThe second and bigger reason is that there is no good solution to bone loss as of yet. The demineralization numbers for long duration flight are just plain scary.Valeri Polyakov didn't suffer crippling bone loss during his 14 month stint in freefall.Googling Valeri Polyakov I found this page:http://www.naturalhealthway.com/noblerex-k1/noblerex-k1-platinum.htmlAt first glance, the page smells like get rich scammers preying on the very large market of gullible overweight people who want to look great without discomfort, time or effort.But Polyakov did enjoy an unusual and noteworthy success. Have the Russians developed an exercise method that's effective? Wish I knew more about Whole Body Vibration System.
Wish I knew more about Whole Body Vibration System.
...the radiation above the Van Allen belts is too nasty for people to survive long term without truely massive amounts of shielding.
In the next 7 years the best we could hope for would be visit to a NEO, L-2 or lunar orbit.
Quote from: MATTBLAK on 09/20/2009 01:39 amIn the next 7 years the best we could hope for would be visit to a NEO, L-2 or lunar orbit.Phobos round trip is easier than the vast majority of NEO round trips.
Quote from: Hop_David on 08/06/2010 04:41 pmQuote from: MATTBLAK on 09/20/2009 01:39 amIn the next 7 years the best we could hope for would be visit to a NEO, L-2 or lunar orbit.Phobos round trip is easier than the vast majority of NEO round trips.Certainly less delta V for a crewed mission, though not for the SEP missions which can't use aerobraking or Oberth effects. Making repeated trips to an NEO will be very difficult. They're only near a small fraction of the time.
3. ... Establish permanent base on Phobos using large scale inflatables (http://forum.nasaspaceflight.com/index.php?topic=18759.0) This focuses on part 2....• Testing a storm shelter – inflating a 5m balloon under the regolith
...2. Send a centrifuge and lots of other stuff to Phobos and have the crew spend 2 years there.
Given a spinning hab, you couldn't bury it.Perhaps some radiation shielding could be enjoyed by having it spin within Stickney crater (this gives shielding from Phobos as well as Mars). Perhaps regolith or water could be exported from Phobos to the spin hab to use for radiation protection.
Quote from: Hop_David on 08/06/2010 07:35 pmGiven a spinning hab, you couldn't bury it.Perhaps some radiation shielding could be enjoyed by having it spin within Stickney crater (this gives shielding from Phobos as well as Mars). Perhaps regolith or water could be exported from Phobos to the spin hab to use for radiation protection.Some research on Earth indicates many humans can handle 4rpm. Then a 25 m radius gives a = .4^2 x 25 = 4m/s, or Mars surface.There's no reason why a 50m wide torus couldn't be inflated under the Phobos regolith (assuming very low tensile strength).
Quote from: alexterrell on 08/07/2010 07:01 amQuote from: Hop_David on 08/06/2010 07:35 pmGiven a spinning hab, you couldn't bury it.Perhaps some radiation shielding could be enjoyed by having it spin within Stickney crater (this gives shielding from Phobos as well as Mars). Perhaps regolith or water could be exported from Phobos to the spin hab to use for radiation protection.Some research on Earth indicates many humans can handle 4rpm. Then a 25 m radius gives a = .4^2 x 25 = 4m/s, or Mars surface.There's no reason why a 50m wide torus couldn't be inflated under the Phobos regolith (assuming very low tensile strength).I like the idea of putting the base within Stickney and burying almost everything under the regolith of Phobos. However, instead of a spinning hab, I'd think that an extremely lightweight electric train running around inside a torus would work. A train can be engineered to be simple and reliable and fixable. The train's length can extend all the way around the torus, thus it wouldn't have a front or tail. Centrifugal force is what you want. How to get centrifugal force in a lightweight and reliable format is one of the interesting questions for a Phobos base and spaceships. I have looked at some pretty lightweight and simple trains and roller coasters... I don't see any advantages to giving angular momentum to the structure that has to deal with the centripetal force. Thus the structure that resists the centrifugal force should not rotate. Let the Phobos centrifugal force train roll on and on in an endless circle. Stops are scheduled every hour on the hour. Maintenance checks are done continuously and automatically. Cheers!Edited.
A rat wheel would do the job, but am trying to imagine how the rat wheel and torus balloon would fit inside plausible fairings. If put inside plausible fairings, seems to me a lot of assembly would be required.
The rat wheel consists of several thousand 8m rigid "planks". These are held parallel to the main axis. They are all connected by thin sheets of Spectra, as well as Spectra cables running through them. All the planks are pushed into the core for transit. Once the rat wheel starts to rotate, the planks extend to make floors. The effect on each of the several floors is like walking on a rope bridge, about 8m in diameter, suspended by flexible sheet walls, with cables running through the planks.All the room walls are also present, as thin flexible sheets.The "bridge", spread over seven floors is 650m long. If each plank is 2cm thick, that needs 13m2 of the payload fairing cross section. I.e, wrapped around the core, they're only occupying a ring 9m in diameter and 1/2m wide. So plenty of room for "rigging" and sheets.So actually packing is easy. Testing the rat wheel before departure will be impossible so hope the CAD models are correct!
An origami rat wheel? Intriguing idea. If the idea's viable, I believe it could be tested in LEO.
If we can assume loose regolith, then it still makes more sense to do a spinning space station. This would be a "dumb-bell" style station where loose regolith is packed into empty fuel tanks and/or external balloon bags for long term cosmic ray shielding and countermass.The "dumb-bell" could be a 120m long beam between a lightweight crew module and a heavier service/supply module. At 2rpm, this provides Mars gravity on the crew side and Lunar gravity on the heavier side. (It can start off life in LEO as a spin gravity research station--one ATV derived MSS module on one side and two MSS modules on the other side.)I'm wary of spin rates greater than 2rpm, so an 80m radius may be the minimum practical for Mars level gravity.
Quote from: IsaacKuo on 08/07/2010 07:11 pmIf we can assume loose regolith, then it still makes more sense to do a spinning space station. This would be a "dumb-bell" style station where loose regolith is packed into empty fuel tanks and/or external balloon bags for long term cosmic ray shielding and countermass.The "dumb-bell" could be a 120m long beam between a lightweight crew module and a heavier service/supply module. At 2rpm, this provides Mars gravity on the crew side and Lunar gravity on the heavier side. (It can start off life in LEO as a spin gravity research station--one ATV derived MSS module on one side and two MSS modules on the other side.)Though "fixing" several thousand tons of regolith to the habitat modules, and accelerating this to 20m/s and supporting it under .38g will be problematic.Perhaps you could launch the modules with a void space ready for filling.
If we can assume loose regolith, then it still makes more sense to do a spinning space station. This would be a "dumb-bell" style station where loose regolith is packed into empty fuel tanks and/or external balloon bags for long term cosmic ray shielding and countermass.The "dumb-bell" could be a 120m long beam between a lightweight crew module and a heavier service/supply module. At 2rpm, this provides Mars gravity on the crew side and Lunar gravity on the heavier side. (It can start off life in LEO as a spin gravity research station--one ATV derived MSS module on one side and two MSS modules on the other side.)
I'd rather wait for some spin rate research, and if possible, ...
... inflate the whole thing on deimos or phobos and then cover in regolith (or inflate in deimos or phobos).
DiZio's work on rotational adaptation has shown that 5RPM is feasible, possibly as high as 10RPM. If people get sick, don't send them. Skylab astros were happily running on the "race track" at rates greater than 5RPM. However, program managers really hate the idea of artificial gravity, so a short-arm centrifuge for exercise sessions is probably all that will be used.
The ring wouldn't need to be sealed at all (in fact, it would best not be sealed), and should be able to be spun-down at any time. Any structural considerations should be handled by the structure of the ring.Just an idea.EDIT: Part of the benefit of this idea is that the whole artficial gravity mechanical system would be inside a pressurized environment, and thus could be fixed mid-flight using conventional hand tools without a difficult and risky EVA.
Are there any possible ramifications of this research for the early manned and robotic missions to Phobos?Martian Moon Phobos May Have Been Formed by Catastrophic BlastAt: http://www.spaceref.com/news/viewpr.html?pid=31665Cheers!
Quote from: HappyMartian on 09/21/2010 02:05 pmAre there any possible ramifications of this research for the early manned and robotic missions to Phobos?Martian Moon Phobos May Have Been Formed by Catastrophic BlastAt: http://www.spaceref.com/news/viewpr.html?pid=31665Cheers!Kind of makes it halfway a Mars surface mission! At least, the remains of an older Mars. It makes it quite likely that fossilized life may be present, if there was such fossilized life on Mars in the distant past.Depending on when life arose and when the catastrophic collision happened, of course.It may mean there are fewer hydrocarbons there, though, which is too bad.
I wonder about that Robotbeat. Martian Moon Phobos May Have Been Formed by Catastrophic BlastAt: http://www.spaceref.com/news/viewpr.html?pid=31665The article notes, "High porosity is required in order to absorb the energy of the large impact that generated Stickney crater..."Other comments in the article also imply the possibility that Phobos could be good at catching comets and meteoroids. The interior of Phobos could be a treasure house of useful material, including hydrocarbons and H2O. Maybe we could envision Phobos as being somewhat like a large scale gel object. I seem to remember that gels have been used to catch micrometeroids...Anyway, this research may make a Phobos mission even more attractive for an early robotic explorer. Cheers!See: http://en.wikipedia.org/wiki/CometEdited.
A further factor is how much gravity difference can the human body take between the toes and the head?We were designed to operate under a nearly fixed amount of gravity with some intermittent turning torque.Human beings are about 2 metres high (6'6").
I agree that astronauts can probably adapt to ~5-10rpm, which should be good enough for Mars-level gravity in something like a Bigelow Sundancer module. Heck, you could just build it after you orbited the module, inside the module. You could have an artificial-gravity section of the module where sleeping, exercising, and perhaps other activities that could benefit from artificial gravity (like fixing or making something... most rapid manufacturing techniques rely on gravity). Also, if even idle activity in artificial gravity is found to be helpful, computers and desks could be placed in the artificial gravity section.The ring wouldn't need to be sealed at all (in fact, it would best not be sealed), and should be able to be spun-down at any time. Any structural considerations should be handled by the structure of the ring.Just an idea.EDIT: Part of the benefit of this idea is that the whole artficial gravity mechanical system would be inside a pressurized environment, and thus could be fixed mid-flight using conventional hand tools without a difficult and risky EVA.
On a long trip, there may well be a need for repairing or even manufacturing parts. Rapid-prototyping machines almost all require gravity to work, especially powder-based ones.
Quote from: Robotbeat on 09/23/2010 03:05 pmOn a long trip, there may well be a need for repairing or even manufacturing parts. Rapid-prototyping machines almost all require gravity to work, especially powder-based ones.For the foreseeable future this won't be an issue and certainly not with current rapid prototype materials. None of them have even a small fraction of the strength of standard aerospace materials so there are no parts that will be repaired by rapid prototypes using today's technologies. If we posit some magic that can rapid prototype out of flight-grade materials, then we may not have to worry about gravity. No sense even putting it on the radar as its a completely "magic" technology at this point Paul
I have been thinking for some time that a major impact event in Mars younger days may have been responsible for a lot of things. Imagine an asteroid striking the planet at what is now the Hellas Basin. This pushed the core of the planet so hard that it bulged out the other side creating Tharsis and the big volcanoes. Phobos and Diemos couold be ejecta fron this event. This could also account for Mars elongated orbit.Anyone Mick.
Quote from: MickQ on 09/22/2010 06:48 amI have been thinking for some time that a major impact event in Mars younger days may have been responsible for a lot of things. Imagine an asteroid striking the planet at what is now the Hellas Basin. This pushed the core of the planet so hard that it bulged out the other side creating Tharsis and the big volcanoes. Phobos and Diemos couold be ejecta fron this event. This could also account for Mars elongated orbit.Anyone Mick.Given the decay in their orbits, one would surmise that the impact was fairly recent (~100 million yrs?) and not early solar system. To create the Tharsis bulge would have been like making Earth's moon.If Phobos is from Mars, it may have less water and hydrocarbons. However, it could be a composite body - it really does a need a manned visit.
Is Phobos tidally locked with Mars, or does it spin?
Quote from: Lars_J on 09/28/2010 01:11 amIs Phobos tidally locked with Mars, or does it spin?It is tidally locked, though it is not in a synchronous orbit so Mars spins beneath it.
Quote from: orbitjunkie on 09/28/2010 02:17 amQuote from: Lars_J on 09/28/2010 01:11 amIs Phobos tidally locked with Mars, or does it spin?It is tidally locked, though it is not in a synchronous orbit so Mars spins beneath it.If I recall correctly, Phobos is above the Mars horizon for something like 4 hours at a time, twice a day, for any location on the surface in a broadly equatorial region. From a base on the Mars facing end of Phobos multiple surface units could be teleoperated in succession during each orbit for hours at a time.Mick
Relaying through a few low-orbit comsats, it could be close to 24x7. I think the rovers already use Mars Odyssey and MRO to relay to Earth and Phoenix used Mars Express. It might be harder to track a spacecraft at Phobos because it's moving faster than Earth (angular speed, not absolute velocity!), but it should be doable.
Recent observations as thermal infrared wavelengths using the Planetary Fourier Spectrometer (PFS) instrument on Mars Express show a poor match between the rocks on Phobos and any class of chondritic meteorite known from Earth.These would seem to support the "re-accretion" models for the formation of Phobos, in which rocks from the surface of the Red Planet are blasted into Martian orbit to later clump and form Phobos."We detected for the first time a type of mineral called phyllosilicates on the surface of Phobos, particularly in the areas northeast of Stickney, its largest impact crater," said co-author Dr Marco Giuranna, from the Italian National Institute for Astrophysics in Rome.These phyllosilicate rocks are thought to form in the presence of water, and have been found previously on Mars."This is very intriguing as it implies the interaction of silicate materials with liquid water on the parent body prior to incorporation into Phobos," said Dr Giuranna."Alternatively, phyllosilicates may have formed in situ, but this would mean that Phobos required sufficient internal heating to enable liquid water to remain stable."
Quote from: alexterrell on 09/27/2010 12:27 pmQuote from: MickQ on 09/22/2010 06:48 amI have been thinking for some time that a major impact event in Mars younger days may have been responsible for a lot of things. Imagine an asteroid striking the planet at what is now the Hellas Basin. This pushed the core of the planet so hard that it bulged out the other side creating Tharsis and the big volcanoes. Phobos and Diemos couold be ejecta fron this event. This could also account for Mars elongated orbit.Anyone Mick.Given the decay in their orbits, one would surmise that the impact was fairly recent (~100 million yrs?) and not early solar system. To create the Tharsis bulge would have been like making Earth's moon.If Phobos is from Mars, it may have less water and hydrocarbons. However, it could be a composite body - it really does a need a manned visit.Alex. I agree. Phobos should be a priority target. I think it was Kkattula who recently posted that it is essentially a NEO with a great view. A perfect place for an outpost to conduct teleoperated research of Mars as well.Mick.
Quote from: MickQ on 09/28/2010 01:06 amQuote from: alexterrell on 09/27/2010 12:27 pmQuote from: MickQ on 09/22/2010 06:48 amI have been thinking for some time that a major impact event in Mars younger days may have been responsible for a lot of things. Imagine an asteroid striking the planet at what is now the Hellas Basin. This pushed the core of the planet so hard that it bulged out the other side creating Tharsis and the big volcanoes. Phobos and Diemos couold be ejecta fron this event. This could also account for Mars elongated orbit.Anyone Mick.Given the decay in their orbits, one would surmise that the impact was fairly recent (~100 million yrs?) and not early solar system. To create the Tharsis bulge would have been like making Earth's moon.If Phobos is from Mars, it may have less water and hydrocarbons. However, it could be a composite body - it really does a need a manned visit.Alex. I agree. Phobos should be a priority target. I think it was Kkattula who recently posted that it is essentially a NEO with a great view. A perfect place for an outpost to conduct teleoperated research of Mars as well.Mick.And:- It can be reached every 2.2 years. NEOs with low delta V will have infrequent access opportunities.- With Mars / Earth aero capture, delta V requirements are low - about 1.2km/s from Earth Moon L1- A SDHLV (e.g. Jupiter 246) with SEP transfer stage can put 50 tons on Phobos.A couple of months ago I became a fan of "Phobos Direct". Ignore Mars and set up a permanent, substantial base on Phobos. Four SEP cargo flights per year deliver 200 tons of supplies every year. Once the base is up, with ISRU and fuel production, exploring, and then settling Mars is "relatively" easy.
Is "Phobos Direct" an actual mission study/proposal or just an idea ?Mick.
Quote from: MickQ on 10/07/2010 05:34 amIs "Phobos Direct" an actual mission study/proposal or just an idea ?Mick.Sadly just an idea - unless I consider my notes and spreadsheets a mission study
I finally found the HEFT study everyone is referring to. Not sure if it's in nasaspaceflight but I found it here in case I'm not the last to read it:http://www.scribd.com/doc/37170377/NASA-future-missions-study-Heft-2
I think it could be adapted to Phobos. The issue I have with NEO missions is they are unique, visit once affairs. That makes them pretty much flags and footprints. Phobos or Deimos is a destination that can be visited every 2.2 years, so long duration infrastructure can be built up with SEP delivered modules.
Quote from: alexterrell on 09/30/2010 09:32 amI finally found the HEFT study everyone is referring to. Not sure if it's in nasaspaceflight but I found it here in case I'm not the last to read it:http://www.scribd.com/doc/37170377/NASA-future-missions-study-Heft-2Thank you for actually posting the link!
Quote from: Warren Platts on 10/08/2010 07:47 amQuote from: alexterrell on 09/30/2010 09:32 amI finally found the HEFT study everyone is referring to. Not sure if it's in nasaspaceflight but I found it here in case I'm not the last to read it:http://www.scribd.com/doc/37170377/NASA-future-missions-study-Heft-2Thank you for actually posting the link!pdf at:http://nasawatch.com/archives/2010/09/human-explorati.html -Alex
Quote from: alexterrell on 10/07/2010 09:56 amQuote from: MickQ on 10/07/2010 05:34 amIs "Phobos Direct" an actual mission study/proposal or just an idea ?Mick.Sadly just an idea - unless I consider my notes and spreadsheets a mission study You have to start somewhere. Care to share what you've done Mick.
Quote from: Robotbeat on 09/07/2010 08:39 pmI agree that astronauts can probably adapt to ~5-10rpm, which should be good enough for Mars-level gravity in something like a Bigelow Sundancer module. Heck, you could just build it after you orbited the module, inside the module. You could have an artificial-gravity section of the module where sleeping, exercising, and perhaps other activities that could benefit from artificial gravity (like fixing or making something... most rapid manufacturing techniques rely on gravity). Also, if even idle activity in artificial gravity is found to be helpful, computers and desks could be placed in the artificial gravity section.The ring wouldn't need to be sealed at all (in fact, it would best not be sealed), and should be able to be spun-down at any time. Any structural considerations should be handled by the structure of the ring.Just an idea.EDIT: Part of the benefit of this idea is that the whole artficial gravity mechanical system would be inside a pressurized environment, and thus could be fixed mid-flight using conventional hand tools without a difficult and risky EVA.Current BA 330 design is too small to accommodate an internal centrifuge. It *could* be done, with 6RPM you are looking at 0.12g, with 8, 0.2g. I would suggest a 10m diameter hab as a minimum (2001 Discovery centrifuge size). At these sizes, too *low* an RPM causes problems with Coriolis forces and walking speeds. But perhaps these aren't as big problems as we think they are.A couple of rings of fluid around the rotation axis should keep instabilities down.Gasbarri P., Teofilatto P. (2009) Fluid ring dampers for artificial gravity spacecraft. Acta Astronautica (64), 1286-1292
The ISRU fuel plant converts Kerogen and Water into LOX and Kerosene (or methane if easier). Then crew ships (and later Mars ships) are fueled up on Phobos. Crew ships then go from Mars to Earth Moon L1 and back on this fuel load.
From alexterrell:QuoteThe ISRU fuel plant converts Kerogen and Water into LOX and Kerosene (or methane if easier). Then crew ships (and later Mars ships) are fueled up on Phobos. Crew ships then go from Mars to Earth Moon L1 and back on this fuel load.It might be unwise to make this an important part of your architecture until we have a better idea of what Phobos is actually made of.
One scenario is that Phobos is resource rich, but buried by 100s of metres in dessicated carbon free dust.
Quote from: alexterrell on 10/09/2010 12:07 pmOne scenario is that Phobos is resource rich, but buried by 100s of metres in dessicated carbon free dust. Then we would need to know what the dust is. With a bit of thought practically anything that burns can be turned into rocket fuel, although the Isp may be low. If the material can be converted into a solid say by pressure or melting then it can be used for construction purposes. Phobos is in a shallow gravity well so even non-reactivate asbestos could be used as say a heat shield on the Mars landers.