PARIS — Mobile satellite services operator Inmarsat is canvassing satellite manufacturers to determine how long it would take to build a Ka-band satellite to back up the three Global Xpress satellites already under construction, industry officials said.

The satellite, tentatively called Inmarsat 6, would be a hedge in the event one or more of the three satellites now under construction by Boeing Space and Intelligence Systems is delayed.

All three of the Global Xpress satellites are scheduled for launch between late this year and the end of 2014 aboard International Launch Services (ILS) Proton rockets.

Officials from London-based Inmarsat declined to comment, but industry officials said Inmarsat was spooked by the July 2 Proton failure that destroyed three Russian government satellites. 

The failure and its spectacular nature, all caught on video — oscillating trajectory on liftoff before tipping over, bursting into flames and then crashing — cast a harsh light on Inmarsat’s sole-source decision for the Global Xpress satellites. The company’s stock tumbled on the London Stock Exchange but has since recovered as details emerged about the relatively easily addressed causes of the rocket’s failure.

Inmarsat officials said at the time of the ILS contract award that they received an exceptionally low price in return for booking all three launches on Proton and that the vehicle’s record justified the choice not to include a second vehicle in the Global Xpress mix.

Early indications are that the Russian-built Proton may return to flight this fall, but bottlenecks in the ILS manifest that have accumulated since the vehicle’s previous anomaly in December are likely to push launch dates further to the right.

Inmarsat had been counting on a first Global Xpress launch late this year, with the two others following in 2014 and global service availability by early 2015. The company is inaugurating a new business with Global Xpress using high-speed Ka-band spot beams to provide volumes more bandwidth than the company’s traditional L-band satellites.

Inmarsat’s contract with Boeing includes an option for a fourth satellite, which in any event will be necessary to provide backup in case one of the other three spacecraft fail. From geostationary orbit 36,000 kilometers over the equator, three satellites can ring the globe with coverage, except for the poles.

The question for Inmarsat is whether exercising the option with Boeing is the best course of action compared to a fresh order for a smaller satellite produced more quickly.

A request for information is often issued in advance of a company’s formal decision on a capital investment. Should Inmarsat decide to go forward with the project, it likely will send out a request for proposals to candidate satellite manufacturers. The company then would need to select a launch vehicle.


Proton Failure Poses Problems for SES, Inmarsat

Peter B. de Selding was the Paris Bureau Chief for SpaceNews.