Blok DM-03
| Manufacturer | Energia & Krasmash |
|---|---|
| Country of origin | Russia |
| Used on | Proton-M · Angara A5 |
| Associated stages | |
| Derived from | Blok D |
| Comparable | Briz-M |
| Launch history | |
| Status | Active |
| Total launches | 8 |
| Successes (stage only) | 6 |
| Failed | 2 |
| Lower stage failed | 1 |
| First flight | 5 December 2010 |
| Last flight | 5 February 2023 |
| Specifications | |
| Powered by | 1 × RD-58MF |
| Propellant | RP-1/LOX |
The Blok DM-03 (Russian: Блок ДМ-03, lit. 'Block DM-03', GRAU index: 11S861-03), is a Russian upper stage used as an optional fourth stage on the Proton-M and Angara A5 heavy-lift rockets. Three have been launched, the first in December 2010; the first two launches failed before fourth stage ignition, the first as a result of a problem with the Blok DM's fuel load. Some versions are also known as Orion.
Initial versions of the Blok DM-03 are powered by a single RD-58M engine, burning RG-1 and liquid oxygen. The last evolution is powered by the improved RD-58MF, a less powerful but more efficient evolution of the venerable engine. It can carry 25% more propellant than the Blok DM-2, which it replaced as a Proton upper stage for some government launches. However most government launches and all commercial missions use the Briz-M instead. The payloads for the first two Blok DM-03 launches were groups of three Uragan-M satellites for the GLONASS programme, with further missions slated to carry three more Uragan-M satellites, and two Ekspress satellites on separate launches. The Blok DM can inject payloads into orbit more accurately than the Briz-M, making it better suited for launching satellites such as the Uragan-M which lack apogee motors.
When production ended in 2012, five Blok DM-03 stages had been produced by RKK Energia, for use on Proton and potentially Zenit rockets. A new version of the upper stage is expected to be introduced once the five launches are complete; all five DM-03s have been slated for Proton launches between 2010 and 2015. During a November 2014 interview, Vladimir Kolmykov, the Deputy General Director of the Chemical Division of Krasnoyarsk Machine-Building Plant, stated that the production of Block-DM was suspended during that year, but work on the stage and development of the RD-58MF resumed during 2015.