- Security Commissioner Eric Paddington
- Jeremy – the Council SRB lab organizer
- Peter Gibson – head of Military Designs
- Margaret Wheeler – President of the Council
- E. Fredman – senior official at Histo-Research
- Goodwin – Fredman’s superior at Histo-Research
- Director Blackwell – of Federal Stockpile Conservation
- Steven Hurst – Richard Hurst’s elder son
- Earl (Hurst) – Steven’s younger brother
- Jennifer Preston – the children’s friend / neighbor
- Edward Milsom – “the Variable Man”
- Richard Hurst – electrical-engineer father of Steven and Earl
- Fleet Commander Tucker – Terran war-fleet commander
- Vice-Commander Dickerson – second-in-command of the fleet
- Joseph Dixon – senior Security officer
- Douglas West – late physicist who discovered the f-t-l principle