Tongue Tied

Arnold Rimmer holds handfuls of Helium-7-rich sand on Planet Rimmer

"Helium seven's incredibly scarce. It's rarer than an un-groped bottom at the BBC in the 1970s."
- Arnold Rimmer

Helium-7 is an extremely rare natural resource. Given its extreme rarity, it is also the most valuable. It was one of the most prized commodities of the Jupiter Mining Corporation. However, it was also one of the most combustible.


Three million years into the future, the JMC mining spaceship Red Dwarf passed by a planetoid in Deep Space which had a record high level of Helium-7 in the sand covering its surface. The boys from the Dwarf took a Starbug down to the surface and planted a flag, with Arnold Rimmer naming it "Planet Rimmer". However, an incoming solar storm forced the Dwarfers to flee, with Rimmer happy enough to get merely a jar of the sand, since that would be enough to make him rich beyond his wildest dreams if he ever got back to Earth in his own time period.

Soon after, Starbug was hit by a Time Wave, which washed up a massive spaceship from the past, SS Enconium, and which was headed directly for Planet Rimmer on a collision course. Determining that a collision would ignite the Helium-7, the Dwarfers decided to dock with SS Enconium and investigate, and in an attempt to avoid a collision.

On Starbug, Rimmer realises that Dave Lister has taken some of the sand

As Starbug headed towards SS Enconium, Dave Lister took some of the Helium-7 sand from Rimmer's jar, with Rimmer soon after looking perplexed as he looked at the jar which was no longer full.

When the Dwarfers were later taken prisoner aboard SS Enconium for breaking its strict anti-criticism laws, they were able to escape the prison cell by exploding grains of Helium-7 rich sand scraped from the bottom of Lister's moon boots. ("Timewave", Series XII)


  • Helium-7 is very reactive and dangerous, evident by the Dwarfers being scared for their lives when realising SS Enconium is on a collision course with Planet Rimmer, and could ignite the Helium-7 on the moon. Kryten notes that such an explosion would be of a magnitude to kill every living thing in that region of space.
  • In the Series XII finale, "Skipper", Rimmer used a Quantum Skipper to explore different dimensions, he came across a dimension where Red Dwarf had never left the Solar System and the Cadmium II radiation leak had never occurred since Dave Lister had noticed and reported the faulty drive plate. Lister was then made captain, but refused a pay off, instead opting for shares in the JMC. When a planetoid full of Helium-7 was discovered by the JMC, it made Lister a fortune through his shares. It is possible that this planet was the same as Planet Rimmer seen earlier in "Timewave".

Behind the Scenes

  • Helium-7 is a real, very heavy isotope of the element Helium, and is a "hyperfragment" that is created in certain nuclear reactions, or under certain conditions in particle accelerators. It is extremely unstable, with a very short half-life of less than a second, and it gives out beta particles and gamma rays as it decays. (See Wikipedia article)