Author Topic: First manned mission to Phobos  (Read 30990 times)

Offline alexterrell

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First manned mission to Phobos
« on: 09/19/2009 10:23 pm »
Following a lot of discussion about Phobos, a potential exploration  scenario might include:
1. Robotic precursor missions, including sample return (Phobos Grunt), and testing of technologies.
2. Short stay mission departing from LEO: 30 to 60 days for a crew of 4-6 on the surface of Phobos.
3. Long stay mission departing from HEO: Establish permanent base on Phobos using large scale inflatables (http://forum.nasaspaceflight.com/index.php?topic=18759.0)
This focuses on part 2.

The mission is assembled in Low Earth Orbit. The crew stay in a Bigelow BA 330 module for 6-9 months out, 30-60 day stay, and 6-9 months return. Water is recycled in the service module.
The mission is launched using cryogenics. If available, a Jupiter Upper Stage with 175 tons of fuel will launch the stack to a Mars Transfer Orbit. Before Mars arrival, dehydrated waste is jettisoned. The mission uses aerocapture around Mars, and then a quick burn to meet with Phobos. The mission settle as Phobos, where crew spend 30-60 days doing a number of tasks:
   Drilling in to Phobos and testing methods of regolith processing;
   Testing water extraction and electrolysis equipment
   Testing a storm shelter inflating a 5m balloon under the regolith
   Testing anchoring methods
   Making observations of Mars possible remote piloting surface vehicles

At the end of the stay, the crew leave behind the Phobos exploration module and return to Earth Transit (using storable propellants). The mission uses aerocapture around Earth to enter a highly elliptical orbit and then a high orbit. An Orion Capsule meets with the BA-330 to return the crew. The BA-330 and service module remains in orbit.

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.

Key components are:
Components   Mass      Notes
BA-330 module   23   tons   Source: Wikipedia
Service Module   10   tons   Incl solar panels, life support, water recycling
Return supplies   4   tons   
Heat shield   3   tons   
Return rocket   5   tons   
Phobos scientific module   10   tons   
Outbound supplies   5   tons   
LEO transfer rocket   12   tons   Based on Jupiter Upper Stage


Mass and Delta-V estimates are attached.

Is this doable for the mass?
Any new developments needed that are not in development?
Does anyone know the layout of a BA-330 module - how many floors, orientation etc. The BA website has nothing.

It fits nicely with the Jupiter 246, given a 175 ton fuel capacity in the upper stage. But it would also work with the ULA EELV approach. There's no need for an Altair lander, but some novel ideas will be needed for testing.

Thoughts?
« Last Edit: 09/19/2009 10:26 pm by alexterrell »

Offline A_M_Swallow

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Re: First manned mission to Phobos
« Reply #1 on: 09/19/2009 11:59 pm »
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?

Online Eric Hedman

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Re: First manned mission to Phobos
« Reply #2 on: 09/20/2009 01:29 am »

Any 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.

A third possible reason if you look at poll numbers is that it might only be another 3 years.  The right track wrong track numbers are usually the best indicator and a majority think we are on the wrong track.

Offline MATTBLAK

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Re: First manned mission to Phobos
« Reply #3 on: 09/20/2009 01:39 am »
In the next 7 years the best we could hope for would be visit to a NEO, L-2 or lunar orbit.
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Offline alexterrell

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Re: First manned mission to Phobos
« Reply #4 on: 09/20/2009 08:43 am »

Any 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.

What's the shortest trip time to Mars and back, without using too much extra propellant. Is it about 18 months? (I would like to see an extra propellant / time saving trade-off chart - any idea?)

Russian(s?) have stayed in space for over a year and survived. Impact exercises help, so I assume the journeys out and back would be spent running around the Bigelow module.

The journey to Mars could use the JUS as a spin weight, but this only weighs 12 tons. If it were joined by the Phobos exploration module, there'd be reeling in issues at Mars arrival. If the JUS were spun at 1g, then the crew might get 1/9g - not sure what effect that has. No reason though why it can't be spun at 3g.

At 3g (for the JUS), you have 36 tons of force. Assume break stree of 100tons, or 1MN. At 2GPA (Spectra) that's 0.5E-3m3. Assume length is 200m, that's 100kgs of fibre, plus reeling mechanism. It means adding 80m/s to the JUS velocity and about 10m/s to the BA330 velocity.

Other than this issue, then the development requirements are:
- Jupiter launch vehicle; or the scheduling of 12 or so EELVs and the development of a capable Earth Departure Stage.
- BA-330 development
- Fun things to do on Phobos - Robotic Razor Clams etc.
- Unmanned precursor missions - it looks like Phobos Grunt won't get there till 2012.

And risk. If you're on Phobos and you hve a propellant leak, not good. (Maybe store the Kerosene inside the BA-330. Oxygen could be replaced by the experimental electrolysis gear.)

So if Obama wanted to do a Kennedy, yes he could.

Offline alexterrell

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Re: First manned mission to Phobos
« Reply #5 on: 08/05/2010 08:25 pm »
Summer holidays in the rain are a good time to revisit this!

After looking at the VASIMR discussion in Advanced Concepts, and replaying the numbers (based on input above, which mostly increases mass), I thought Id revisit a Phobos mission.

The principle is to use electric propulsion to send as much as possible to Phobos on a three-year journey. The crew then travel on a normal Hohmann trajectory (with Oberth plus aerocapture) for a month long stay at Phobos.

The equipment required:
   An exploration ship something that can support a crew of six for a two-year mission into deep space. The exploration ship is also equipped with heat shields to allow aerocapture at Mars and Earth. Solar powered with water and air recycling. Assumed mass 60 tons.
   A 1MW VASIMR based tug. Empty mass is 10 tons and it take 20 tons of Argon fuel. Uses thin film solar cells for light weight and resistance to Van Allen radiation. Able to carry
     -   60-90 tons LEO to L1, in 12-18 months, using 10-15 tons of Argon (and return empty)
     -   60 tons LEO to Phobos, in 36 months, using 20 tons of Argon (with no return)
     -   A hypergolic rocket stage, empty mass 5 tons, and 35 tons of fuel with Isp of 325 seconds.

The exact scheduling depends on the capability of HLV available. The VASIMR tug carries 60 tons and masses 20-30 tons depending on fuel load.

Schedule
In the first year, three Solar Electric Tugs depart for Phobos. Each carries one hypergolic rocket stage, and 20 tons of exploration equipment and supplies.

In the second year, the Exploration Ship is launched with 15 tons of supplies (for the outbound journey). A Kerolox rocket stage is also launched, with 60 tons of Kerosene / Lox. These elements weigh 142 tons. These are taken by two Solar Electric tug missions to Earth-Moon L1.

In the third year, an Orion mission delivers the crew of 6 (assuming Orion can be equipped for 6) to L1. The crew depart for Phobos, using Mars aero capture (total delta V 1.8km/s). On arrival at Phobos, the crew have a month on the surface. Experiments will include ISRU experiments and tests on suitability of Phobos as a base.

Note:
1.   An extra Solar electric tug could bring supplies, and an artificial gravity environment, to allow a 2 year stay.
2.   An extra Solar tug could bring a Mars lander/ascent vehicle to allow the crew to spend a few weeks on the surface of Mars.

For the return, two of the hypergolic stages are used to propel the exploration ship (with 15 tons of new supplies)  back to Earth (delta V 1.9km/s). The third hypergolic stage is spare / left for future missions. The exploration ship is aerocaptured to enter a Highly Elliptical Earth Orbit.

An Orion mission docks with the Exploration Ship and brings the crew home. A small rocket stage parks the Exploration Ship at L1 for the next mission. (By this time a propellant depot is being created).

Launches required:
   5 HLV cargo of circa 70 tons to LEO
   5 Solar Electric Tugs of 20-30 tons (Falcon 9H?)
   Crew delivery mission (J130 or Falcon9 combination?)
   Crew collection mission (J130 or Falcon9 combination?) 

IMLEO ~ 550 tons.

The following mission to Phobos will start a permanent base with ISRU to support Mars landings.

Thoughts?

Offline Hop_David

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Re: First manned mission to Phobos
« Reply #6 on: 08/05/2010 10:45 pm »
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.

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.html

At 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.


Online Robotbeat

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Re: First manned mission to Phobos
« Reply #7 on: 08/05/2010 10:54 pm »
There are also drugs which can help counter-act bone loss, and we haven't done a lot with those in manned missions, even though we could. The drugs we have now are pretty phenomenal, at least for osteoporosis.
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Offline MickQ

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Re: First manned mission to Phobos
« Reply #8 on: 08/06/2010 01:55 am »
Alex.

Do we know anything certain about the resources available on Phobos for ISRU ?

Nick.

Offline alexterrell

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Re: First manned mission to Phobos
« Reply #9 on: 08/06/2010 07:10 am »
Alex.

Do we know anything certain about the resources available on Phobos for ISRU ?

Nick.
Nothing certain, I believe, until Phobos Grunt get's there. That was meant to launch this year but has been put back 2 years.

There was a great suggestion here to crash Mars Express into Phobos, observed by the NASA Mars orbiter, to get spectral composition.

We do know that the density of Phobos is about 2, which implies it's carbonaceous chondrite, with high water content. It may even have Kerogen - a source of carbon and Nitrogen. It could also be a "rubble pile". I would take this to mean assume zero tensile strength in the regolith. That presents problems, but also opportunities - you can bury a base for perfect shielding from cosmic rays and micro-meteorites.

If this is all proved, then I think it makes Phobos the most attractive destination for a base:
- Water
- Very low energy access - a single SDHLV launch with electric thrust can take c 60 tons to Phobos.
-  A large inflatable base complete with rotating gravity section could be buried (without the need for radiation and micro-meteorite protection, a SDHLV launched inflatable base could be huge - say a 50m diameter torus).
- Once ISRU is working, access on demand to the Mars surface
- In the longer term (after a decade or two) great possibilities with tethers

Anyway, this really needs a proof of concept mission - say the 200KW version of VASIMR (as planned for ISS) to take a 10 ton robotic cargo to Phobos to do some serious drilling.

Offline alexterrell

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Re: First manned mission to Phobos
« Reply #10 on: 08/06/2010 07:16 am »
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.

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.html

At 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.


Along time ago I went to a lecture given by a Skylab astronaut / Doctor.

NASA research discovered that the bones and joints need impact to prevent / slow down demineralisation (exercise bikes can help with muscle). On Earth, we get this from walking and jogging (and playing squash:) ). The Doctor came up with a treadmill which holds you down. I suspect the vibration system is to give some impact to the joints - it sounds scary.

Given medicines and machines, I see two solutions:
1. Put up with it for a short stay mission, total time away about 18 months. Polyakov did 14 months.
2. Send a centrifuge and lots of other stuff to Phobos and have the crew spend 2 years there. 

Offline Proponent

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Re: First manned mission to Phobos
« Reply #11 on: 08/06/2010 07:24 am »
Wish I knew more about Whole Body Vibration System.

Something along these lines is not actually too unusual in gyms these days.  The claim is that your muscles are engaged all of the time to counteract the vibration.  I tried it out once; I think the gadget was called "VibraplatePowerPlate" or something like that.  It didn't leave me much impressed, certainly not impressed enough to pay to use it after the half-hour free trial session.  But my experience and negative gut reaction is hardly a scientific trial.

I've long thought that the zero-g exercise wheeze that might catch on would be the centrifuge: get a high-speed workout at high-g.
« Last Edit: 08/09/2010 01:28 am by Proponent »

Offline tankmodeler

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Re: First manned mission to Phobos
« Reply #12 on: 08/06/2010 02:28 pm »
9 month travel legs on 2+ year duration trips to anywhere are unlikely unless and until we have a proper solution for radiation effects on humans. Bone loss is bad, but, perhaps managable, but so far the radiation above the Van Allen belts is too nasty for people to survive long term without truely massive amounts of shielding. Not just bunkers for solar flares, but shielding for the whole ship that reduces background radiation levels to really, really low levels. Medical science over the past 30 years has been consistently lowering the radiation doses that are considered safe. They are currently at a small fractrion of levels that were considered OK in even the mid 80s.

For BEO missions, radiation is the elephant in the room and it gets precious little attention out of the specialist community.

Unless we have a truely stupendous upmass capability (think nuclear pulse Orion or Sea Dragon) radiation exposure will likely drive us to NERVA or nuke powered, high-thrust Ion type high/very high ISP propulsion systems so that the trip can be made boosting all/most of the way to get trip times down in the 2-3 month span and stays at the destination can be accomplished in one close approach period of 6-9 months as opposed to being spread out over 2 + years.

That sort of mission isn't going to happen any time soon and not at all unless NASA starts to put some serious money into nuke propulsion. Which they ain't. And it ain't on their radars, neither.  :)
« Last Edit: 08/06/2010 02:29 pm by tankmodeler »
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Offline alexterrell

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Re: First manned mission to Phobos
« Reply #13 on: 08/06/2010 02:40 pm »
Let's hope this works out:
http://forum.nasaspaceflight.com/index.php?topic=22414.0

It seems a fair amount of research got done on magnetic propulsion, but not much on the easier matter of shielding.

One of the advantages of Phobos is likely the ease of in-situ shielding.

Online Robotbeat

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Re: First manned mission to Phobos
« Reply #14 on: 08/06/2010 04:12 pm »
Just because medical doses of radiation have declined doesn't mean it's really that dangerous. I'm not convinced that the cosmic radiation is dangerous enough to double the mission mass. I haven't seen a good case. I mean, yeah, if you can get good cosmic radiation shielding for low mass, then why not, but otherwise, it's worth the slightly increased risk of cancer. Considering the lowering of the life expectancy just by the LOC risk alone, the lowering of life expectancy from cosmic radiation is minimal, even on 2-year trips.

In fact, there's evidence that the body responds to low levels of non-acute radiation by increasing the mechanisms for radiation damage repair, which may actually help reduce the risk of acute radiation. There are also antioxidant cocktails which do a lot to reduce the cellular damage caused by radiation (most of the damage is related to oxidation stress, so addressing that can reduce the damage), perhaps by quite a bit.

There are people who live long, healthy lives in Ramsar, Iran at annual radiation levels (132 mSv annually) up to about 25% of what astronauts en route to Mars would experience. Some even claim that the low level of radiation actually makes them more healthy (the same way that the stress of exercise stimulates the repair mechanisms of the body), although either way, it's clear that that level of radiation isn't a significant risk compared to the other risks astronauts face.

The risk of cosmic radiation is based on extrapolation from very high radiation doses where the body doesn't have enough time to repair the damage. I am not convinced the risk is as high as some say it is when the body is given enough time to repair the damage.
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Offline Hop_David

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Re: First manned mission to Phobos
« Reply #15 on: 08/06/2010 04:33 pm »
...the radiation above the Van Allen belts is too nasty for people to survive long term without truely massive amounts of shielding.

That is one reason I beat the drums about mining ice at the lunar poles for export to EML1 or 2.

A ship filled at an EML1 propellent depots has a 2.4 km/sec advantage over LEO. A lower delta V budget enables a more massive trans-Mars vehicle. A vehicle which could include more radiation shielding.

Besides supplying EML1 depots with Lox and LH2, the lunar poles could also export water there. Water is very good radiation shielding as well as necessary for life support. Loft the trans-Mars vehicle from earth with hollow walls, this would be less massive. At EML1 the hollow walls could be filled with lunar water.

Offline Hop_David

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Re: First manned mission to Phobos
« Reply #16 on: 08/06/2010 04:41 pm »
In 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.

Offline alexterrell

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Re: First manned mission to Phobos
« Reply #17 on: 08/06/2010 07:06 pm »
In 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.

Online Robotbeat

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Re: First manned mission to Phobos
« Reply #18 on: 08/06/2010 07:19 pm »
In 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.
SEP can use aerobraking, just not aggressive aerobraking or aerocapture.
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Offline Hop_David

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Re: First manned mission to Phobos
« Reply #19 on: 08/06/2010 07:35 pm »
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

This is perhaps doable.

...
2. Send a centrifuge and lots of other stuff to Phobos and have the crew spend 2 years there. 

Although a solution to bone loss & other health issues, this sounds substantially more difficult and expensive than the buried Bigelow balloons you mentioned earlier.

How much more expensive? I don't know.

Some unanswered questions are minimum gravity needed to stay healthy and maximum angular velocity humans could live comfortably in.

Given high angular velocity and low gravity, spin habs could be much smaller and less expensive.

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.

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