The Race2Recovery team is trying to complete the Dakar Rally to raise funds for Help for Heros.
The charity is raising funds for the Tedworth House recovery and rehabilitation centre in Wiltshire.
The two US Marines involved with the race are also raising funds for the Heros Project which supports injured service men and women in America.
More top news
Jeremy Corbyn addressed supporters from the top of a fire engine after a rally spilled out into the street because so many people turned up.
In March 1992, Cilla Black became an ITV News reporter for National Trading Places Day to raise money for charity.
Police launched a manhunt after a woman was shot in the eye with an airgun, leaving her with 'life-changing' injuries.