1. Mission Objectives

As the sister mission to Mars 1M No.1, its primary objectives were identical, designed for a flyby trajectory of Mars:

Engineering:

• Validate the first-generation interplanetary spacecraft platform (1M Series).
• Test three-axis attitude control systems in deep space.
• Assess the feasibility of long-range (interplanetary) communication.
• Test the performance of the new Molniya launch vehicle and the Blok-L escape stage.

Scientific:

• Obtain images of the Martian surface during the flyby.
• Measure the interplanetary magnetic field and search for a Martian magnetic field.
• Study the solar wind spectrum and cosmic rays outside Earth's magnetosphere.
• Detect the flux rate of micrometeorites.
• Search for signs of organic matter using spectroreflectometry.

2. Probe Specifications (Mars 1M Platform)

The Mars 1M probe was the first deep-space probe design developed by the OKB-1 design bureau. The specifications for Mars 1M No.2 were identical to its predecessor.

• Total Mass: 640 kg
• Science Payload Mass: 10 kg
• Architecture: A cylindrical, pressurized, and hermetically sealed module (0.9 m diameter, ~2 m height) housing the main avionics and batteries. This design was used to simplify thermal control.
• Attitude Control: Three-axis stabilization system. Orientation was determined by a primary sun sensor and secondary star sensors. Actuation was achieved via cold nitrogen gas thrusters and reaction wheels.
• Power: Two solar panels (total area 2 m²) charging a set of silver-zinc batteries.
• Communications: A primary high-gain antenna (HGA) in a parabolic grid shape for telemetry and image transmission, supplemented by omnidirectional low-gain antennas (LGA).
• Propulsion: A trajectory correction system (KDU) based on a bipropellant engine (UDMH/Nitric Acid) designed for a single mid-course correction (TCM).

3. Scientific Instrumentation

The 10 kg instrument package included:

• Fluxgate Magnetometer: Mounted on a boom to minimize magnetic interference from the probe.
• Scintillation Counter and Gas-Discharge Counter: To measure cosmic ray radiation.
• Piezoelectric Micrometeorite Detector: To register particle impacts.
• Ion Trap: To measure solar wind characteristics.
• Spectroreflectometer: To analyze reflected light for absorption bands associated with hydrocarbons (an early attempt to search for biosignatures).
• Imaging System (TV Camera): Designed to activate during the flyby.

4. Launch Vehicle and Escape Stage

The mission used the same launcher model as its predecessor, the Molniya 8K78.

• Stages 1 & 2 (Blok B, V, G, D, and Blok A): The standard R-7 core and strap-on booster configuration.
• Stage 3 (Blok-I): A new, more powerful third stage, derived from the Vostok rocket's Blok-E stage but using a more efficient RD-0107 engine.
• Stage 4 (Blok-L): A critical escape stage. It was designed to ignite in a parking orbit (LEO) to inject the probe onto a hyperbolic escape trajectory toward Mars.

5. Launch Failure Analysis

1. Initial Sequence: The launch occurred on October 14, 1960, just four days after the failure of Mars 1M No.1.
2. Failure Event: During ascent, a failure occurred in the second stage (Blok A) of the Molniya rocket.
3. Root Cause: Analysis determined that a leak of oxidizer (cryogenic liquid oxygen) in the second stage was the primary cause.
4. Failure Result: The spilled liquid oxygen leaked and came into contact with the upper stage fuel lines. This caused the kerosene fuel line intended for the third stage (Blok-I) engine to freeze solid.
5. Impact: Although stages 1 and 2 separated, the third stage was unable to ignite due to the frozen fuel line. The vehicle failed to achieve orbital velocity.
6. Fate: The payload (Mars 1M No.2) and the rocket's upper stages failed to reach Earth orbit and were destroyed upon atmospheric re-entry.

6. Technical Conclusion

The Mars 1M No.2 mission was a launch failure[cite: 271]. Unlike its sister mission, which failed due to vibrations in the third stage [cite: 22], this failure originated from a plumbing problem (oxidizer leak) in the second stage, which had a cascading effect preventing third-stage ignition. The probe never had the opportunity to be tested. The USSR did not publicly acknowledge this attempt, which was tracked by Western intelligence as Korabl 5.