In consumer space, 69 KB of RAM (138 x 4 kbit chips) would cost around $1700 70s dollars for the entire package, ~$10k in modern dollars.
Radioationed hardened for space though — $50k-$100k in 70s dollars, roughly the price of a Silicon Valley house back then - $300k-$600k in today's money.
Wouldn't they just put a lead plate around the computer? That can't cost 100k in 70s
consumer space and space space chips.