As long as a fuel distribution network is established first, commercial crew vehicles plus in-space habs/tugs can do it all. This is likely the reason the anti-depot crowd is adamant in opposition.
Quote from: AncientU on 10/15/2014 12:26 pmAs long as a fuel distribution network is established first, commercial crew vehicles plus in-space habs/tugs can do it all. This is likely the reason the anti-depot crowd is adamant in opposition.You don't need to establish depots first, a spacecraft can act as it own depot just as ISS and Russian stations before it have been doing for decades.
There is still no significant move within NASA towards reusable spacecraft, or even boosters, while other institutions like the Air Force and DARPA are now pushing rapidly in that direction. Funding for propellant depots is virtually nonexistent, and any refueling efforts are aimed primarily at refueling and servicing existing satellites that were never designed to be refueled. Taking another look at this document, five years after its initial release, can give us a precautionary view of where not to go in space (and Mars) mission design.
Doesn't really matter what you call it... when you have refueling technology on the (reusable) vehicles and the means to distribute fuel/refuel where and when you need it, you're good to go. Anywhere.
Quote from: AncientU on 10/15/2014 04:38 pmDoesn't really matter what you call it... when you have refueling technology on the (reusable) vehicles and the means to distribute fuel/refuel where and when you need it, you're good to go. Anywhere.Exactly, but my point is that we've had the necessary technology for years. If NASA wants to build a transfer stage, let them start with a refuelable SM and leave launch vehicles and capsules to the market by buying services competitively. Later that SM can be enlarged to a storable L1/L2 based pump-fed transfer stage for manned exploration.
I don't know I agree. People are still very skeptical about commercial crew, think that ONLY the "big boys" can do it, and at ridiculous cost and about half a century's worth of time.
Can Dragon 2 do a lunar orbit mission without modified propulsion?We know a lunar flyby with Dragon and FH is possible. The upper stage even would have enough delta-v for LOI but it won't last long enough without significant modification if at all. The idea is finding a TLI trajectory that minimizes LOI delta-v at expense of more delta-v for TLI. I am sure some modifications are possible but is it enough? It would not need a circularized lunar orbit. Just an elliptical orbit that would be easy to leave for trans earth injection too. It is not something one can take out of a delta-v map. But with plenty of abort fuel and a not so heavy Dragon is it achieavable? Ideally with enough fuel for a propulsively assisted parachute land landing.Such an orbit may not be suitable for research but would be appreciated as a tourist flight.Edit: The idea behind this is that SpaceX may not be willing to do major engineering for a modified Dragon but willing to sell a flight for a tourist operator.
Just stick a Super Draco and lots of hypergolic tanks in the trunk. But like Baldusi posted. you need longer duration ECLSS, long range communication, navigation and ground tracking & Communication network (NASA is not going to provide the DSN time).For tourism, think a free return orbit like Apollo 8 is all that is required initially.
A really, really high lunar orbit (or EML2) is probably feasible without extra propulsion (may need some light-weighting, however), if you're willing to do a week or two trip time to the Moon's vicinity.There's no "just" about adding a hypergolic stage or service module. (and you wouldn't use Superdracos, they have really crappy Isp and far more thrust than needed... instead, use an array of regular Dracos). It'd be a significant endeavor. Of course it could be done, but it wouldn't be free.
I'm CONFIDENT that this is at least the tenth time this has been discussed.
Quote from: Robotbeat on 11/25/2014 03:41 amI'm CONFIDENT that this is at least the tenth time this has been discussed.I believe you are right. I tried to avoid that by very specifically stating I am looking for a solution without modifications of propulsion. And if that is not possible just forget about it.
For tourism, think a free return orbit like Apollo 8 is all that is required initially.
Quote from: GWH on 07/27/2017 08:16 pmQuote from: ThereIWas3 on 07/27/2017 07:55 pmQuote from: GWH on 07/27/2017 07:31 pmHow anyone GETS to the lander though is anyone's guess.Some Dragon or CST-100 type vehicle?Yeah one would probably be better off discussing that in more detail here: https://forum.nasaspaceflight.com/index.php?topic=35787.100Probably wouldn't be quick and easy. Starliner is limited to 60 hour free flight, Dragon at least lacks the dV, and is a tight ride. ....False, on both accounts. And yeah, you should have discussed it in that thread.
Quote from: ThereIWas3 on 07/27/2017 07:55 pmQuote from: GWH on 07/27/2017 07:31 pmHow anyone GETS to the lander though is anyone's guess.Some Dragon or CST-100 type vehicle?Yeah one would probably be better off discussing that in more detail here: https://forum.nasaspaceflight.com/index.php?topic=35787.100Probably wouldn't be quick and easy. Starliner is limited to 60 hour free flight, Dragon at least lacks the dV, and is a tight ride. ....
Quote from: GWH on 07/27/2017 07:31 pmHow anyone GETS to the lander though is anyone's guess.Some Dragon or CST-100 type vehicle?
How anyone GETS to the lander though is anyone's guess.
At most, Mr. Ferguson stated his desire for Starliner to employ 24-hour launch to docking profiles – due in part to the vehicle’s design, which limits its free flight capability (from launch to docking and then undocking to landing) for an entire mission to just 60 hours.