1. So it looks like a SD-HLV is being built first.2. taking a 45mT Orion into the realms of possibility.3. The hypergolic AJ-10 would not suffer the boiloff problems
Is it technically feasible to launch the Astronauts in a Lunar Lander connected to the EDS on the SLS and use the Lander as the LAS and lifeboat ?
No one would ever consider doing such a thing.
It's a powered descent vehicle. If it is well above the atmosphere it can dock with the waiting Orion and the crew can come back on that if they need to.
If the descent module engine fails you could have parachutes on the ascent module and come down on that.
Mars has an atmosphere so they will not be wasted on a Lander.
So it can perform LOI, have greater shielding and/or carry some of the lunar payload. An unmanned version seems a good fit for the Delta IV Heavy which will be cheaper than a SLS especially if it looks like Ares V. Just doing some unconventional out of the box thinking to see if there is any mileage in the idea.
Don't we want a lander that can eventually float on Titan ?
This one has redundant support structure and costs associated with it.
Quote from: Downix on 09/20/2010 02:04 amThis one has redundant support structure and costs associated with it. If your lander is planning to enter Mars it will need heat shielding anyway to resist that atmosphere although granted it's a lot thinner. If you also make the ascent module heat resistant with parachutes you also have greater crew safety if that module fails to launch off Mars successfully as the crew can abort to the surface and await rescue. The real trick would be in tying up the two different requirements of aborting from Earth ascent and descending /ascending into Mars in one piece of hardware without major mass growth. The other obvious benefit of this architecture is that you don't have to lift a specific LAS on the Orion launcher leaving more usable mass for Orion.
Quote from: marsavian on 09/20/2010 05:03 amQuote from: Downix on 09/20/2010 02:04 amThis one has redundant support structure and costs associated with it. If your lander is planning to enter Mars it will need heat shielding anyway to resist that atmosphere although granted it's a lot thinner. If you also make the ascent module heat resistant with parachutes you also have greater crew safety if that module fails to launch off Mars successfully as the crew can abort to the surface and await rescue. The real trick would be in tying up the two different requirements of aborting from Earth ascent and descending /ascending into Mars in one piece of hardware without major mass growth. The other obvious benefit of this architecture is that you don't have to lift a specific LAS on the Orion launcher leaving more usable mass for Orion.For mars lifting Orion is the least of your worries. Orion on a mars trip at best would be a craft used to send crew to the stack and return after. Most of the mass will not be Orion or the lander plus no way you are going to get a mars trip in 1.5 launches.
Oddly if he didn't use SLS, it could be made to work with a phase II EELV. One core sized powerful enough to lift a 40 ton Orion to LEO and the combined sized powerful enough to lift 70 tons or so to LEO.
Quote from: Downix on 09/20/2010 02:04 amThis one has redundant support structure and costs associated with it. If your lander is planning to enter Mars it will need heat shielding anyway to resist that atmosphere although granted it's a lot thinner. If you also make the ascent module heat resistant with parachutes you also have greater crew safety if that module fails to launch off Mars successfully as the crew could then abort to the surface and await rescue. The real trick would be in tying up the two different requirements of aborting from Earth ascent and descending /ascending into Mars in one piece of hardware without major mass growth. The other obvious benefit of this architecture is that you don't have to lift a specific LAS on the CEV launcher leaving more usable mass for the CEV.
Quote from: pathfinder_01 on 09/18/2010 06:57 pmOddly if he didn't use SLS, it could be made to work with a phase II EELV. One core sized powerful enough to lift a 40 ton Orion to LEO and the combined sized powerful enough to lift 70 tons or so to LEO. That's something I suggested a couple years ago or so when discussing 'clean sheet' options when A I/V were just starting to go wrong... Develop EELV upgrade capable of launching Orion in a single stick configuration and use the three-body heavy version of it for the HLV... I was shot down in flames... didn't gain traction then don't expect it will now either, though as more time passes it looks more and more like the only sane and potentially affordable way to do it... Probably have to see another TOTAL clusterfudge again before it'll be considered... Later! OL JR
{snip}And, playing devil's advocate a moment, IF a failure on ascent led to a second reentry and landing, what exactly would the crew "be rescued" by??
If we're going to Mars, we will take a Lander designed for Mars. If we're going to the moon, we will take a lander designed for the moon. There is little advantage in having one design intended for both, and the result would be a vehicle sub-optimal for both worlds.
{snip}If we are going to maintain the capability to land on the moon while we go for Mars (I certainly hope no one here is arguing that we shouldn't), it would sure be a lot cheaper to maintain production infrastructure for one type of lander rather than two. You'd probably want more thrust for Mars, so either have engine mounts left empty for the moon (like DIRECT's boattail) or design the lander so it can take either RL-10s or RL-60s...
If your lander is planning to enter Mars it will need heat shielding anyway to resist that atmosphere although granted it's a lot thinner. If you also make the ascent module heat resistant with parachutes ...
If we're going to Mars, we will take a Lander designed for Mars. If we're going to the moon, we will take a lander designed for the moon. There is little advantage in having one design intended for both
Rocket men are too mass fixated, so heat shields on lunar landers will not survive. What may survive is common cabins - the Mars lander reuses the lunar landers controls, avionics, life support system and airlock.
Who said anything about a heat shield? {snip}
Okay, fine. But I didn't say anything about heat shields.
Who said anything about a heat shield? This is fully propulsive landing on Mars with plenty of margin.
http://www.grc.nasa.gov/WWW/K-12/airplane/atmosmre.html ?
I wonder (and wonder why I'm wondering) whether it would be cheaper/easier to supply a Mars base in an ice-poor area by using a mass driver at the lunar north pole, or by just trucking ice overland...
Luke you committed such blasphemy as to suggest putting Orion on an EELV gasp! What other blasphemy will you commit next! It is politics that are damaging NASA. The companies\people involved in STS don’t want to be locked out of the replacement. Apollo and Ares both had the same problem. Apollo decided that time was of the essence and developing a totally new rocket to send Apollo to LEO was not a good idea. They took the Saturn I and developed it to the Saturn IB and got on to the hard work (the lunar stuff). Ares figured that NO launcher was available to send people to the ISS and therefore spent time and money that should have gone to Ares V and lunar systems. The end result was that the planned gap was widened and commercial is looking like a better bet. Anyway why did griffin choose a .5 launch anyway? It just adds problems. A capsule sized for lunar work is going to mass much more than a capsule sized to be an ISS taxi. A 15MT launcher could be more than enough for an ISS taxi, but way too weak for lunar one. It forces you to develop two totally new rockets from scratch. Even Apollo didn’t do that.Were politics so entrenched that he couldn’t develop an LEO Orion (with small service module) launch able on Atlas then develop BOE Orion with larger service module launched on NASA rocket?
Quote from: marsavianIf your lander is planning to enter Mars it will need heat shielding anyway to resist that atmosphere although granted it's a lot thinner. If you also make the ascent module heat resistant with parachutes ...Quote from: SparkyIf we're going to Mars, we will take a Lander designed for Mars. If we're going to the moon, we will take a lander designed for the moon. There is little advantage in having one design intended for bothThe ULA paper says their DTAL lunar lander could be modified for Mars as a straightforward increase in volume and thrust. E.g., I ran the numbers for an ACES-71-based lander (with an ascender with somewhat enlarged tanks) would have enough delta v to do a fully propulsive landing without need of TPS's or parachutes, and still have enough propellant leftover for the ascender to get back to low orbit. Thus both landers could come from the same assembly line.