Active On-Board Hydrogen Maser for Radioastron Space Mission VCH-1010

VCH-1010 is an on-board hydrogen frequency standard designed to provide a highly stable reference signal for the space telescope of the Space–Ground Radio Interferometer during radio astronomy research.

The device generates a stable 1 pulse per second (1 PPS) signal throughout the "RadioAstron" mission.

The output of the device is also used for the excitation of a carrier frequency of 15 GHz for high informational radio channel (VIRK) transmitter, which is also a phase-stable channel for measuring parameters of the On-Board Hydrogen Maser.


Output signals nominal values: 1 Hz, 5 MHz, 15 MHz
Relative frequency accuracy ±3×10−13 (with periodic adjustments by Astro Space Center of PN Lebedev Physics Institute)

Frequency stability 5 MHz (Allan deviation for   
5 MHz signal)
1 s ≤3.0×10−13
10 s ≤3.0×10−14
100 s ≤7.0×10−15
1000 s ≤3.0×10−15
1 hour ≤2.0×10−15
1 day ≤5.0×10−15

at ±1 °C ambient temperature change in operating temperature range and temperature change rate of no more than 0,3° C/hour

Long term frequency stability <±2,0×10–14/day
Temperature sensitivity(ambient temperature changes within ± 1°C) <±5,0×10–15 Power supply sensitivity (changes within ±1 V) <±2,0×10–14
Magnetic field sensitivity(changes within ±1 Gs) <±2,0×10–14
Harmonic distortion in 5 MHz and 15 MHz output signals, less than - 30 dB
Non-Harmonic distortion in 5 MHz and 15 MHz output signals, less than −100 dB for <100kHz carrier offset
SSB phase noise spectral density, no more than

 (10±3) Hz  −120 dB/Hz 
 100 Hz±10 %  −140 dB/Hz 
 1 kHz±10 %  −145 dB/Hz 
 10 kHz±10 %  −150 dB/Hz 

In terms of resistance special factors the Hydrogen Maser meets the requirements of section 3.3 of the general technical requirements to scientific equipment of the spacecraft "Spektr-R".

Dimensions: ∅460×729 mm.
Weight: 60 kg.