The Navigator satellite bus


General architecture of the Navigator platform. Credit: NPO Lavochkin

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At the turn of the 21st century, NPO Lavochkin, a key Russian satellite developer, proposed a standard satellite bus which could serve as the basis for a wide range of missions. It would feature systems designed to work in the vacuum of space and therefore would not need pressurized compartments, which were often prone to failure. The platform would also be able to maintain attitude control in space along all three axis with higher accuracy than the previous-generation spacecraft available for Russian scientific and application missions. A total of four reaction wheels would be installed onboard forming a shape of a pyramid to provide redundancy, even though any of the three such devices is enough for the three-axis attitude control.

Dubbed Navigator, the vehicle was adopted for the Elektro-L and Elektro-M meteorological satellites, as well as for the Spektr-R (Radioastron), Spektr-RG (Rentgen), Spektr-UF, Gamma-400, Spektr-M (Millimetron) space observatories and the Arktika remote-sensing and communications satellites. As of 2008, Spektr-R and Gamma-400 missions were expected to use a basic Navigator platform, while Spektr-RG and Spektr-UV telescopes would need some adaptation in case of their launch into the L2 libration points. A version of the platform designated Navigator-M would be used in the Spektr-M project.

As of 2010, NPO Lavochkin was apparently bidding the Navigator platform in government tenders as a base for Arkon-2 and Astrometria missions. (434)

According to NPO Lavochkin, the Navigator platform was designed to work on geostationary, Sun-sunchronous, highly elliptical Earth orbits and even near the so-called Libration or Lagrangian points, essentially in deep space. The satellite based on that platform could be integrated with Soyuz, Zenit or Proton launchers.

An onboard flight control complex, BKU, of the Navigator platform was developed by MOKB Mars.

The Navigator platform was known to include following key systems:

  • Main radio complex;
  • Attitude control system;
  • Power supply system;
  • Thermal control system;
  • Autonomous electronics module;
  • Low-gain telemetry antenna and feed system;
  • High data rate communication radio link;
  • Up-down phase transfer radio link;
  • Solar panel attitude control system;
  • Orbit correction engines.

The propulsion system of the standard Navigator platform included four orbit-correction engines with a thrust of 5 Newtons and eight attitude-control thrusters with a thrust of 0.5 Newtons.


Known specifications of Navigator platform (410):

Dry mass of the platform
850-980 kilograms; (757 kilograms*)
Maximum propellant load
540 kilograms; (175 kilograms*)
Maximum payload mass
2,600 kilograms
Propellant components
Frequency range of onboard radio system
Communications range
200 - 2,000,000 kilometers
Navigation accuracy
2 angular seconds*
Stabilization accuracy
2.5 degrees*
Average stabilization rate
0.36 degrees per second*
Maximum reappointing rate
0.25 degrees per second*
Maximum available power supply for payloads
600 - 1,150 Watts; (500 Watts*)
Onboard power
27 ±1.35 Volts
Operational life span
5 years
Onboard propellant supply
287 kilograms**

*according to "Astrofizecheskiy proejkt Spektr-Rentgen-Gamma, FKP-2015 RF," October 2006;

**for Spektr-R mission

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Page author: Anatoly Zak; Last update: June 19, 2019

Page editor: Alain Chabot; Last edit: January 22, 2011

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Navigator bus

The hexagon-shaped Navigator spacecraft bus was expected to serve as the base for a number of Russian science and application missions, such as Elektro-L and Spektr-RG. Credit: IKI


Assembly of the Navigator service module for the Spektr-RG mission at NPO Lavochkin. Click to enlarge. Credit: Roskosmos