@Jim: you are right that propellant might indeed be a problem. So yes, rather a long-term thing, if anything. Perhaps the propellant could eventually be baked out of the Phobos regolith, solar wind implanted H, Ar (for ion propulsion) and O from silicates or oxides should be available. Alternatively, a solar/laser sail? I am not saying this is something that can/will be done from day one when the station is built. Its just a possible further application down the road (granted, if a source of propellant can be found). But perhaps I am indeed underestimating the fuel needs.I also wasn't suggesting to move the entire station to the target orbit. Servicing would need a small "sortie" vehicle with a reasonable delta-V budget. This.could be smaller than in Earth orbit due to the slower orbital velocities.
A dry-run is absolutely going to happen in any mission as complex as Mars landing, NASA is planning to send Orion on a dry-run mission around to moon first unmanned then manned before trying anything, and that is a just the moon a body 3 days away that's already been landed on. It is not a matter of going to Phobos because we want to study it so specifically, we can get to NEA much more easily, it's just something to do when on a dry-run mission that would be happening if Mars had no moons at all.
With their large and easily damaged solar panels it is unlikely that SEP tugs and SEP transfer vehicles will land on Mars. They will stay in orbit. Will they be left by themselves? Or docked to an orbiting spacestation?Any spacestation and associated propellant depot would need setting up.
I feel that the moons (and any station on them) should come after the parent planet. As noted upthread, they are of less direct scientific interest. Any preliminary robotic test runs for, say, Deimos/Phobos ISRU (I'm in the Deimos camp), could hypothetically be secondary payloads on a manned mars surface mission.
Quote from: Robotbeat on 05/20/2016 07:39 pmQuote from: Jim on 05/20/2016 01:26 pmQuote from: Phil Stooke on 05/19/2016 05:46 pmPhobos operations are the Apollos 8 and 10 to landing on Mars's Apollo 11. A full dress rehearsal mission - with useful science content including Phobos and Deimos exploration (much simpler lander required) and operation of assets on Mars, especially sample collection. Imagine for instance sample collection of polar volatiles, with maybe a 48 hour travel time to the Phobos and/or orbital base for quick analysis rather than trying to keep a cryogenic sample in good shape for an 8 month trip to Earth. That would be a really good precursor to the first Mars landing. Probably essential, I would suggest, just like Apollos 8 and 10.Such missions are not needed and would be a waste of resources. Actually, they would not be like Apollo 8 & 10 because MOR (the Martian equivalent of LOR) is not likely going to be the conop (example, Mars Direct doesn't use MOR) and hence the missions would be dead ends. Jim is a semi-closeted SpaceX fan, as we can see.The NASA PoR (or the closest we have to one) uses Mars-Orbit-Rendezvous. Of all the different NASA paths to Mars, basically all assume MOR. SpaceX intends to go the Mars Direct route by skipping a separate transit vehicle.Long term MOR between transit vehicles and landers is the only way to get any kind of colonization going. A direct flight is simply untenable due to vehicle amortization, for a first mission I could see it being done but it would only be a stepping stone.
Quote from: Jim on 05/20/2016 01:26 pmQuote from: Phil Stooke on 05/19/2016 05:46 pmPhobos operations are the Apollos 8 and 10 to landing on Mars's Apollo 11. A full dress rehearsal mission - with useful science content including Phobos and Deimos exploration (much simpler lander required) and operation of assets on Mars, especially sample collection. Imagine for instance sample collection of polar volatiles, with maybe a 48 hour travel time to the Phobos and/or orbital base for quick analysis rather than trying to keep a cryogenic sample in good shape for an 8 month trip to Earth. That would be a really good precursor to the first Mars landing. Probably essential, I would suggest, just like Apollos 8 and 10.Such missions are not needed and would be a waste of resources. Actually, they would not be like Apollo 8 & 10 because MOR (the Martian equivalent of LOR) is not likely going to be the conop (example, Mars Direct doesn't use MOR) and hence the missions would be dead ends. Jim is a semi-closeted SpaceX fan, as we can see.The NASA PoR (or the closest we have to one) uses Mars-Orbit-Rendezvous. Of all the different NASA paths to Mars, basically all assume MOR. SpaceX intends to go the Mars Direct route by skipping a separate transit vehicle.
Quote from: Phil Stooke on 05/19/2016 05:46 pmPhobos operations are the Apollos 8 and 10 to landing on Mars's Apollo 11. A full dress rehearsal mission - with useful science content including Phobos and Deimos exploration (much simpler lander required) and operation of assets on Mars, especially sample collection. Imagine for instance sample collection of polar volatiles, with maybe a 48 hour travel time to the Phobos and/or orbital base for quick analysis rather than trying to keep a cryogenic sample in good shape for an 8 month trip to Earth. That would be a really good precursor to the first Mars landing. Probably essential, I would suggest, just like Apollos 8 and 10.Such missions are not needed and would be a waste of resources. Actually, they would not be like Apollo 8 & 10 because MOR (the Martian equivalent of LOR) is not likely going to be the conop (example, Mars Direct doesn't use MOR) and hence the missions would be dead ends.
Phobos operations are the Apollos 8 and 10 to landing on Mars's Apollo 11. A full dress rehearsal mission - with useful science content including Phobos and Deimos exploration (much simpler lander required) and operation of assets on Mars, especially sample collection. Imagine for instance sample collection of polar volatiles, with maybe a 48 hour travel time to the Phobos and/or orbital base for quick analysis rather than trying to keep a cryogenic sample in good shape for an 8 month trip to Earth. That would be a really good precursor to the first Mars landing. Probably essential, I would suggest, just like Apollos 8 and 10.
We really should send some probes to those moons, just as we should investigate the lunar poles.Precursor missions (that answer basic questions that could allow us to make informed decisions about destinations before committing to absurdly expensive HSF architectures) just fall through the gap between planetary science and HSF. It is depressing.
I don't see how separating them improves vehicle amortization to any significant degree, and it may make things worse. You'll still need amortization of the in-space element in addition to the large lander.
Quote from: KelvinZero on 05/27/2016 11:09 amWe really should send some probes to those moons, just as we should investigate the lunar poles.Precursor missions (that answer basic questions that could allow us to make informed decisions about destinations before committing to absurdly expensive HSF architectures) just fall through the gap between planetary science and HSF. It is depressing.I couldn't agree more. Problem is, as I'm sure you've noticed, is that Mars itself overshadows Phobos and Deimos. The last Discovery mission announcement included at least 3 proposals but none were selected (Venus and the asteroids became the current candidates). At this rate, I suspect human footprints will be on them before any landing pads. The best candidate for a decent visit between now and the 2030s, albeit in the form of a 'passing glance' of sorts, will be from NeMo, the next generation Mars orbiter. As a benefit, its spiral entry via solar electric propulsion will allow multiple flybys of Deimos and Phobos as it descends through high to low Mars orbits. It is supposed to include radar and infrared instruments so on the good news it will be the best flybys the moons will ever see.However this is supposed to be about putting stations on Phobos, so talking about probes is slightly distracting from topic. My opinion on actual Mars moon stations is that they're unnecessary as opposed to either probes or an orbital vehicle visiting them and putting permanent equipment on Mars itself.
Japan is going to do a Phobos sample return mission and NASA will hop on board that. So you'll get data that way.
From the standpoint of using Phobos as an Interplanetary transshipment transfer point, it is to deep into the Mars gravity well. The heavier elements being the interplanetary craft vs the SSTO craft would more logically place such a station at Deimos not Phobos. A lot like EML2 would be a similar transfer point. Characteristics: high orbit less delta V required of interplanetary craft. Phobos would only be useful in the scenario of a Mars SSTO that is DV challenged. The SpaceX BFS(MCT) would easily reach Deimos without having to refuel since it is supposedly being designed to reach Mars escape from Mars surface. Plus the sophistication of large cycler interplanetary craft, transshipment points, etc is fairly later in the Mars colonization/exploration timelines like 20 years after first man landing.
On another point in a three body system like the two moon Mars system doing a 90 degree inclination change is rather easy by heading out from Phobos to Deimos using a gravity turn to change the inclination then circularizing at the desired orbit height or performing a direct return entry. The problem is that the maneuver still does not come cheap (DV wise) but significantly less than the alternative with also a bigger problem of a narrow window spaced at large intervals of time. Such a maneuver would not be a unplanned event but one planned literally months/years in advance suitable for planned deployments but not rescue or ad-hoc missions. A BTW you can use the Moon the same way but it sort of defeats the purpose since the DV needed to get to it and back may be larger than just landing back on earth and launching again into the inclination you want. Orbital Mechanics: Gravity assist is your friend.
Atlas & redliox: You have it backwards you want to have your point for transfer between in-space vehicles and landers right at the atmospheric interface so each craft type spends essentially all of it's time and energy in the flight regime for which it is optimized, that will result in overall system optimization. That would mean low orbit is ideal and Phobos is preferable to Demos.
While your right that being high in the gravity well such as EML-1&2 is advantageous it would be the place to transfer cargo between cis-planetary in-space vehicles and helocentric transfer in-space vehicles. I think we will have this distinction at the Earth end of the logistical chain because Earth Lagrange points are at roughly the halfway point of the entire DeltaV span between LEO and LMO. But the Martian gravity well is sufficiently small relative to the velocity needed to transfer to Mars that it makes little sense to make another transfer point their. The two break points at or near atmospheric interfaces and one in gravitational 'divide' should suffice.