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djr's user avatar
djr
  • Member for 6 years, 9 months
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17 votes

Do companies/governments ever sell satellites that are already in space?

14 votes

Puzzler - which spacecraft(s) incorporated real wood structural elements?

13 votes

What would one need to do to get an amateur satellite into orbit?

9 votes
Accepted

Is HAN-water propellant "green" enough to ever be used in a cubesat?

8 votes

Is it true that hydrogen is the only practical fuel for upper stages?

6 votes
Accepted

Missions at or soon-to-be at Mars and their DSN "codenames"?

6 votes

Why not build rockets out of composite materials?

6 votes
Accepted

What is the minimum number of RCS thrusters capable of stabilizing a satellite against an arbitrary rotation?

5 votes

How might the experience of a trip to Mars differ in comfort and heath impact from a stint on the ISS?

5 votes
Accepted

Why Never-EVER Land?

5 votes
Accepted

How fast is the onset of periodic eclipse for a spacecraft in LEO?

5 votes

If I wanted to try to terraform Mars, who would have the authority to stop me?

5 votes
Accepted

Has "parasitic radar" ever been used in space?

4 votes

Radioisotope thermoelectric generator behavior on reentry

4 votes
Accepted

cross parachute - drag coefficient

4 votes

If we were to land on Phobos, what could we gain?

3 votes

What would be a few challenges to build a landing strip on mars?

3 votes
Accepted

Yikes! How did we miss 2017 VL2?

3 votes
Accepted

At what Mars-time did Perseverance land?

3 votes

Why do New Shepard's drogue chutes just "hang there" for ten seconds before deploying the main parachutes? What happens during that time?

2 votes

Why don't unmanned launch vehicles include launch escape system for payload?

2 votes

Is a space probe communication relay possible?

2 votes

What if anything makes launching a recovered SpaceX rocket from a drone ship implausible?

1 vote
Accepted

Are these images from Planet Labs? Are the images publicly available?

1 vote
Accepted

What is "trade space" in the context of libration orbit mission design? (used in trade analysis, launch window analysis and trade study)

1 vote

Why put SunRISE in the graveyard? Why will it "fly slightly above geosynchronous orbit"?