SpaceX Dragon 2 Updates and Discussion - Thread 3

[Lars-J]

So many little details for this flight...

Looks like SpaceX added an extension plate to the footrest to decrease Hayley's knee bend angle when seated.

I'm assuming that its to help lower the stress on the prosthetic during launch and landing.

It could be that, but also because of her height perhaps? She appears to be the shortest person to fly in Dragon.

[docmordrid]

A poster on the Inspiration4 discussion thread mentioned in passing that a private customer was looking to fly a flight that exceeded the altitude of the highest Gemini flight. I am guessing this would be with Dragon 2. The only thing is I thought the Inspiration4 mission was already at the maximum safe altitude for Drsgon 2?

http://www.collectspace.com/news/news-021820a-space-adventures-spacex-crew-dragon.html

[...]Space Adventures' free-flyer mission will provide up to four crew members with the opportunity to break the world altitude record for a private citizen spaceflight. The current orbital record of 853 miles (1,373 kilometers) was set in September 1966 by Charles "Pete" Conrad and Richard "Dick" Gordon on NASA's Gemini 11 mission. (Apollo astronauts, including Conrad and Gordon, later flew farther from Earth on missions to the moon, but the Gemini 11 record stands for the highest Earth orbit reached by a crewed spacecraft.)

https://spaceadventures.com/space-adventures-announces-agreement-with-spacex-to-launch-private-citizens-on-the-crew-dragon-spacecraft/

[...]Space Adventures, Inc. has entered into an agreement with SpaceX to fly private citizens on the first Crew Dragon free-flyer mission. This will provide up to four individuals with the opportunity to break the world altitude record for private citizen spaceflight and see planet Earth the way no one has since the Gemini program.

[Star One]

A poster on the Inspiration4 discussion thread mentioned in passing that a private customer was looking to fly a flight that exceeded the altitude of the highest Gemini flight. I am guessing this would be with Dragon 2. The only thing is I thought the Inspiration4 mission was already at the maximum safe altitude for Drsgon 2?

http://www.collectspace.com/news/news-021820a-space-adventures-spacex-crew-dragon.html

[...]Space Adventures' free-flyer mission will provide up to four crew members with the opportunity to break the world altitude record for a private citizen spaceflight. The current orbital record of 853 miles (1,373 kilometers) was set in September 1966 by Charles "Pete" Conrad and Richard "Dick" Gordon on NASA's Gemini 11 mission. (Apollo astronauts, including Conrad and Gordon, later flew farther from Earth on missions to the moon, but the Gemini 11 record stands for the highest Earth orbit reached by a crewed spacecraft.)

Thanks. Will that mean expending the F9 first stage and therefore pushing the price up?

[MATTBLAK]

It might; they may use one of the oldest and most-used Falcon 9 first stages in that instance.

[Star One]

It might; they may use one of the oldest and most-used Falcon 9 first stages in that instance.

That would be breaking new ground in itself using such an old stage on a manned flight.

[Rekt1971]

Thanks. Will that mean expending the F9 first stage and therefore pushing the price up?

Inspiration4 had a circular 575km orbit, perhaps if the perigee remained ∼200km (or a little higher) then Dragon might have enough fuel to push the apogee to ∼1400km.

[savantu]

Might be a silly question  , but could do you a Molnya type orbit with Dragon 2 ?
Something like 600x40,000 ? I know you'll pass through the Van Allen belts like 4x/ day, but for 2 days, hey, I think there would be interest anyway.

[cscott]

Putting the apogee near the poles would completely avoid the van Allen belts.  More details (including how the Apollo trajectories were shaped to avoid the Van Allen Belts) here:
https://science.thewire.in/the-sciences/apollo-11-van-allen-radiation-belts-translunar-injection/

[AstroWare]

Inspiration4 had a circular 575km orbit, perhaps if the perigee remained ∼200km (or a little higher) then Dragon might have enough fuel to push the apogee to ∼1400km.

I have been thinking about this too.

I think another method to reach higher orbit would be to lower the launch inclination. I4 used the ISS trajectory to maintain abort zones and recovery procedures. But a mission which was trying to reach a higher orbit and willing therefore to assume the increased risk, could opt to launch at 28 degrees.

I4 also had dragon inserted into a low circular parking orbit. I'm sure this is safer if an immediate return is required. But F9 could fly a trajectory which is elliptical to begin with.

We also know F9 flies a less efficient ascent due to possibility of abort and the risk of high G exposure to the crew. Idk what the limit is (dragon structural or human) but there could be an option to fly a higher risk ascent to gain performance.

elliptical orbit + low inclination + modefied ascent and injection orbit?

Wonder where all that gets you in terms of apogee.

( I'm assuming they accept the same van Allen belt transit risk as Gemini and just limit the number of passes )

[Barley]

The delta-v from a 200x200 orbit to a 200x1400km orbit is about 320m/s.

I believe you can get about 120m/s with a launch azimuth of 90 rather than 45degrees to the ISS.
The remaining 200 m/s should be within the capability of Dragon 2.  You need to reserve only minimal fuel to deorbit if your heat shield is up to it.

So the mission should be possible without expending a booster, even without any additional performance from stage 2, or mass reducing Dragon.

[kevinof]

The delta-v from a 200x200 orbit to a 200x1400km orbit is about 320m/s.

I believe you can get about 120m/s with a launch azimuth of 90 rather than 45degrees to the ISS.
The remaining 200 m/s should be within the capability of Dragon 2.  You need to reserve only minimal fuel to deorbit if your heat shield is up to it.

So the mission should be possible without expending a booster, even without any additional performance from stage 2, or mass reducing Dragon.

Beiji (can't remember his last name) from Spacex said that they still had 50% propellant reserves left after the flight yesterday so it would seem it could go longer or higher ( but maybe not both).

[Hitech]

Did anyone else notice the streaming liquid seen in the video of the second stage and the green tinged exhaust toward the end of the burn?

[joek]

Did anyone else notice the streaming liquid seen in the video of the second stage and the green tinged exhaust toward the end of the burn?

No; nothing appeared anomalous. Please provide screen shots of what you think was odd.

[Kiwi53]

It might; they may use one of the oldest and most-used Falcon 9 first stages in that instance.

They'd more likely use an earlier, less used, but hard to refurbish booster.
From what I've read on here, it seems like the later F-9 boosters are much easier and much cheaper to refurbish than the early ones, to the extent that SpaceX are reluctant to use the early ones unless they're not going to refurbish them.

[Zed_Noir]

It might; they may use one of the oldest and most-used Falcon 9 first stages in that instance.

They'd more likely use an earlier, less used, but hard to refurbish booster.
From what I've read on here, it seems like the later F-9 boosters are much easier and much cheaper to refurbish than the early ones, to the extent that SpaceX are reluctant to use the early ones unless they're not going to refurbish them.

Well there are the two early Block 5 Falcon Heavy side boosters (B1052 & B1053) in storage.

[CuddlyRocket]

A poster on the Inspiration4 discussion thread mentioned in passing that a private customer was looking to fly a flight that exceeded the altitude of the highest Gemini flight. I am guessing this would be with Dragon 2. The only thing is I thought the Inspiration4 mission was already at the maximum safe altitude for Drsgon 2?

[...]Space Adventures' free-flyer mission will provide up to four crew members with the opportunity to break the world altitude record for a private citizen spaceflight. The current orbital record of 853 miles (1,373 kilometers) was set in September 1966 by Charles "Pete" Conrad and Richard "Dick" Gordon on NASA's Gemini 11 mission. (Apollo astronauts, including Conrad and Gordon, later flew farther from Earth on missions to the moon, but the Gemini 11 record stands for the highest Earth orbit reached by a crewed spacecraft.)

As Gemini 11 was not a private citizen spaceflight, all they have to do "to break the world altitude record for a private citizen spaceflight" is to fly higher than Inspiration 4, which currently holds that record.

Defining an Earth-orbital altitude record as they do gives a reasonable target to aim at with plenty of room on the upside. (Anyone know the maximum possible Earth orbit as so defined? Presumably higher than geostationary orbit and there may be some fancy orbit that avoids the Moon!) Having a record with incremental steps for improvement is often a driver for technological improvements.

Although in these early days of private citizen spaceflights, SpaceX might be well advised not to permit too many compromises on safety, signed waivers notwithstanding. We don't want politicians or regulators to have an excuse to clamp down on such flights.

[hektor]

https://twitter.com/SciGuySpace/status/1439950546732036098?s=20

[joek]

...

Cool. Maybe will incent others (CST-***) to also go after that market.

[abaddon]

...

Cool. Maybe will incent others (CST-***) to also go after that market.

The opposite, I think.  Based on what we know, CST is more expensive by enough that the best way for them to sign commercial flights would be limited availability of Dragon.  The more Dragon opportunities there are, the harder it would be to swallow the price difference.

Boeing could subsidize the difference to try and win some contracts on a more competitive price basis, but that doesn't really seem like their MO.

[ZachF]

...

Cool. Maybe will incent others (CST-***) to also go after that market.

The opposite, I think.  Based on what we know, CST is more expensive by enough that the best way for them to sign commercial flights would be limited availability of Dragon.  The more Dragon opportunities there are, the harder it would be to swallow the price difference.

Boeing could subsidize the difference to try and win some contracts on a more competitive price basis, but that doesn't really seem like their MO.

They'd have to wait for Vulcan to become man-rated too, since all of the remaining Atlas-Vs are already spoken for.