Inmarsat’s telemetry network for rockets ready for launch

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TAMPA, Fla. — British satellite operator Inmarsat is preparing to use its telemetry relay network to support rocket launches this year for the first time, according to a company executive. 

Peter Hadinger, Inmarsat’s chief technology officer, said “some customers” are looking at using the operator’s new InRange launch support service in 2022 after it demonstrated the capability during ground tests.

Using Inmarsat’s L-band constellation, Inmarsat says InRange will save launch providers from spending money on ground stations and other terrestrial infrastructure for tracking rockets in flight.

While there are typically command and telemetry links at a launch site to support immediate monitoring and flight termination systems, rockets can quickly go out of range when they travel beyond the horizon.

Launch providers typically use downrange stations on land or on ships to maintain telemetry through all stages of flight and payload deployment, Hadinger said, but “these are expensive to maintain.”

“New launch providers, often using new launch locations, start off with no downrange ships or stations and these can be quite expensive to establish,” he said.

“Further, terrestrial tracking visibility restricts the range of trajectories that can be supported and stations must often be staffed and configured weeks ahead of a launch which impacts responsiveness.”

For decades NASA has used its Tracking and Data Relay Satellite (TDRS) spacecraft as an “all-seeing telemetry receiver,” Hadinger added, but this system “is expensive and is offered to others only on an as-available basis.”

Inmarsat’s U.S. subsidiary April 21 became one of six companies to win a slice of $278.5 million in funding to demo services that could help replace TDRS. 

TDRS was set up in the 1980s to provide a relay between the United States and spacecraft in low Earth orbit — in addition to occasionally supporting launches when a rocket travels beyond the sight of its launch range.

Inmarsat plans to use its $28.6 million share of the funding to demo InRange and other services for LEO spacecraft with its network of geostationary orbit satellites.

The funding is a “large step up” from the roughly $350,000 in funds Inmarsat received from the UK Space Agency for InRange last year, Hadinger noted.

Following investments from industry, the company had only secured around $500,000 in funding for InRange as of March 2021.

Mitsubishi Heavy Industries, the prime contractor for Japan’s next-generation H3 launch vehicle, has partnered with Inmarsat to develop InRange. 

Safran Data Systems, the telemetry solutions provider based in Europe and North America, and U.S. antenna maker Haigh–Farr are also partners and are focusing on InRange’s L-band transmitter and antenna design.

Hadinger expects the InRange-supported launches that could take place this year will still use telemetry and command facilities at the customer’s launch site for local control during liftoff, and other critical flight termination functions while the rocket is still in view.

“For the planned missions, InRange will get them extended telemetry through all stages and payload deployment that they would not otherwise have,” he said.

“It is also being looked at carefully by launch providers with existing telemetry networks for both operating cost reasons and because they can optimize their launch trajectories for certain orbits where today they have to take sub-optimal routes just to stay in contact.

“By optimizing they can increase the payload mass that can be offered and reduce the orbit raising required of the satellite — both quite valuable.”

The InRange services will initially use the four I-4 spacecraft that Inmarsat operates to provide global L-band coverage.

In the future, Hadinger said the service will connect to its upgraded I-6 satellites. 

Mitsubishi Heavy Industries launched the first I-6 satellite in December and the all-electric propulsion spacecraft is due to reach its orbital position later in 2022.

Other companies that won NASA funding to test how commercial satellites could support missions currently using TDRS also aim to demonstrate launch support services.

One of those winners, Viasat, is seeking regulatory approval to buy Inmarsat for $7.3 billion.

The other winners are Amazon’s Kuiper Government Solutions, SpaceX, SES Government Solutions, and Telesat U.S. Services.