- PROBE
- Investigation
- Exploratory space launch
- Inquest
- Voyager or Pathfinder
- Ask questions
- Deep-space vehicle
- NASA project
- Pioneer 1, for one
- Serious investigation
- Voyager 2, for one
- Investigate
- Poke into
- Delve
- Look into
- Scrutiny
- Data-collecting craft
- Official investigation
- Dig deep
- Explore deeply
- Legislative investigation
- Seriously look into
- Space exploration vehicle
- Space explorer (Ford)
- Thorough investigation
- Voyager 1, e.g.
- Examine thoroughly
- Look into closely
- Inquiry
- Research project
- Delve into
- Dig into
- Penetrating investigation
- Major investigation
- Investigate in depth
- Dig deeply for answers
- Extended investigation
- Deep dig of a sort
- Temperature sensor
- Investigate thoroughly
- Investigation by a legislative committee
- Senate investigation
- Unmanned craft
- Lawmaker's activity.
- Examine.
- Search into
- Search
- Surgical instrument
- Search thoroughly
- Lunar ___
- Test
- Explore
- Exploratory device
- Perscrutation
- Deep-space mission
- Grand jury's activity
- Space explorer
- Exploratory spacecraft
- Government investigation
- Certain NASA launch
- See circled letters
- Nonhuman explorer
- Dig for answers
- Do some digging
- Really dig
- Voyager 1, for one
- Get personal, say
- Search extensively
- Explore thoroughly
- Doctor's examination or instrument
- Investigation with much digging
- Investigate completely
- Congressional investigation
- Question closely
- Voyager or Pathfinder, e.g.
- FBI investigation, e.g.
- Mueller's Russiagate investigation, e.g.
- Senate investigation, e.g.
- Exploring device
- Exploratory expedition
- NASA vehicle
- Exploratory machine
- NASA's Voyager 2, e.g.
- Galileo, for Jupiter, e.g.
- Interplanetary traveler
