SpaceX News

[krenshala]

Nice to see that went well.

This bodes very well for the future. We hope to launch the first crews to the ISS within about two years, plus or minus six months. -- Elon Musk

[hanelyp]

Escape rockets worked well enough, even if there was one that shut down early according to reports. But the way the capsule tumbled would be "exciting" if an astronaut had been on board.

[Tom Ligon]

http://www.space.com/29328-new-spacex-c ... video.html

Cool! A Space X rep reported this news today at the H2M Summit, with pictures but no video. The rockets on the capsule are not just for escape, but should serve for landings eventually.

They 3D print them!

[Maui]

Escape rockets worked well enough, even if there was one that shut down early according to reports. But the way the capsule tumbled would be "exciting" if an astronaut had been on board.

Although I think what would get me the most, is after the drone chutes have deployed when the main chutes are released. Looks like there would be (on top of the tumbling) a nice stomach drop with that release (plus a split second of "the chutes are okay right?")

[Giorgio]

They 3D print them!

Exactly! I consider this the biggest improvement of SPACEX so far, even more than the first stage landing.
The possibility to rely on a standard protocol for 3D printed components for rocket engines will give a huge impulse to space development.

[GIThruster]

"As long as short-term regional advantages are given precedence over what is the best deal for the country at large, Orion will continue to be the expensive and obsolete fiscal black hole that it is."

Nicely done comparison: http://www.thespacereview.com/article/2743/1

[Skipjack]

Escape rockets worked well enough, even if there was one that shut down early according to reports. But the way the capsule tumbled would be "exciting" if an astronaut had been on board.

Although I think what would get me the most, is after the drone chutes have deployed when the main chutes are released. Looks like there would be (on top of the tumbling) a nice stomach drop with that release (plus a split second of "the chutes are okay right?")

Better that than dying during a catastrophic failure of the booster, I suppose. I think the problem was that due to a slightly mismatched mixture ratio on one engine, they missed their target altitude. That meant they had less time for the capsule to coast after trunk separation. That in turn meant less time for the capsule to stabilize itself in a heatshield forward position (the design of the capsule is such that it would be self stabilizing in that orientation) and that meant that the capsule was still tumbling when the drogues and main chutes deployed.
That is at least my personal guess about all this.

[Maui]

I wouldn't be surprised if they really didn't care about or plan at all to minimize tumbling, though. As you say, survival is the goal, not preserving your lunch.

[Skipjack]

I wouldn't be surprised if they really didn't care about or plan at all to minimize tumbling, though. As you say, survival is the goal, not preserving your lunch.

Well, they dont really have to do anything about the tumbling. The capsule shape is self stabilizing in a heatshield forward position. Given enough time, it would always stabilize itself.

[D Tibbets]

My 2 cents worth. The space craft tumbled quickly and may have tumbled or rotated multiple times before it slowly stabilized rear first, and even then it would probably oscillate back and forth for many seconds. For a pad abort or low altitude abort, there would be no time for the capsule to stabilize. In this case active thrusters and/ or a stabilizing drogue chute is needed, as in this case. It did look like the drogue chute was deployed almost to late, A little later and it may have become fouled with the capsule. I wonder if the deployment was timed or fired when senors detected the target attitude. The Orion capsules first(?) test was a failure because it was unstable and tumbling after extraction from the C17 launch airplane. The chute became fouled and the craft tumbled to the ground.

I also speculate that the weather was more problematic than they anticipated. With a small decrease in final speed, the capsule was drifting close to shore and communication seemed to suggest that it may have been coming close to exiting the test range. I'm not sure what range safety action could be used at that point, perhaps cutting the parachutes lose. When the capsule hit the water it briefly became a speed boat as the parachutes dragged it, presumable due to significant surface winds.

PS: The engines are not only for escape. They provide the deorbiting burn,and possibly soft landing on land. If there is enough fuel, the engines may also provide some orbital maneuvering capacity.That these functions are all managed by one system has to introduce significant advantages over a dedicated abort rocket system that is thrown away (with it's launch weight penalty) after it is no longer needed, as in Apollo or Orion. The down side is that the retained engines make the craft heavier for re entry and passive landing. And for orbital maneuvering, much smaller/lighter rockets would suffice. The final balance requires some slid rule manipulation. The retained full capacity engines with associated fuel loading, may not give much advantage from a speed consideration, but mostly an economical benefit from re-usability.

Dan Tibbets

[jnaujok]

The capsule still retains the regular Draco thrusters in clusters around either side of the Super Draco ports. Those thrusters are used for most of the orbital maneuvering on a typical ISS approach or similar mission. I see the Super Dracos more for something like orbital maneuvers to a much higher orbit, or, potentially, for a lunar insertion orbit. I'd imagine they could also potentially be used for boosting the space station to a higher orbit, which the Progress is used for now. Not sure if the commercial docking port is structurally strong enough for that though.

[D Tibbets]

The lower power manuevering thrusters would allow for orbital maneuvering , though I was thinking of larger orbital adjustments , not because the thrusters are more powerful, but because more fuel is reserved for the mission.

All but the final landing retro thrust could be handled by the standard thrusters, assuming there is not a launch abort. Ther is a increased level of redundancy which has to help safty. If some of the orbital maneuvering engines failed, the super draco thrusters could compensate, perhaps not as smoothly, but they woulod get the job done.

With that in mind, I wonder if the final product will have an emergency parachute only water or land touchdown capacity. The super draco rocket fuel supply might be depleted by use as a substitute for the regular orbital thrusters. The capsule might not be reusable, but if it allows for crew survival, it would be a victory.

Dan Tibbets

[hanelyp]

Heat shield as a crumple zone in case of a hard landing?

[D Tibbets]

Heat shield as a crumple zone in case of a hard landing?

That and good couches. Experience with combat vehicles and IEDs has led to significant blast (G force) mitigation efforts within the vehicle.
I think the G force mitigation efforts in a Soyuz is based mostly on astronaut/ cosmonaut fitted seats/ couches with a thin padding. The careful fitting helps to distribute the force evenly over the entire body so that there is less likelihood of a focused effect- like breaking the back. With the volume of the dragon or Orion, the couches themselves could have much more shock absorbing features.

Also the Dragon still needs the parachutes for descent (I think), tough some modest weight might be saved by using smaller chutes.

Dan Tibbets

[krenshala]

Heat shield as a crumple zone in case of a hard landing?

That and good couches. Experience with combat vehicles and IEDs has led to significant blast (G force) mitigation efforts within the vehicle.
I think the G force mitigation efforts in a Soyuz is based mostly on astronaut/ cosmonaut fitted seats/ couches with a thin padding. The careful fitting helps to distribute the force evenly over the entire body so that there is less likelihood of a focused effect- like breaking the back. With the volume of the dragon or Orion, the couches themselves could have much more shock absorbing features.

Also the Dragon still needs the parachutes for descent (I think), tough some modest weight might be saved by using smaller chutes.

Dan Tibbets

I'm not sure if it is still the plan, but original Dragon specs were to have a parachute for emergencies but otherwise use the thrusters alone for a powered soft-landing.