20
opportunity
|
6
reentry
|
2
feasibility
|
1
astrobiology
|
20
probe
|
5
balloons
|
2
economics
|
1
atmosphere
|
20
reliability
|
5
amateur-rocketry
|
2
asteroid
|
1
exoplanet
|
20
rovers
|
4
lander
|
2
cassini
|
1
hydrogen
|
12
spacex
|
4
mercury
|
2
interstellar-travel
|
0
reduced-gravity-cooking
|
12
launch
|
4
shielding
|
2
planetary-protection
|
0
vacuum
|
12
communication
|
4
temperature
|
1
research
|
-1
heat
× 2 |
12
falcon-heavy
|
3
satellite-flare
|
1
isru
|
-1
aerobraking
|
8
low-earth-orbit
× 2 |
3
microgravity
|
1
nuclear
|
-1
design
|
6
rockets
× 2 |
3
health
|
1
lunar-landing
|
-1
lift
|
ShadoCat
