In this task, we ask you to rewrite a sentence in simple English without changing its general meaning. Essentially, you want to make the sentence easier to read by using simpler words, utilizing more straightforward sentence structures, and omitting non-essential information etc.
One example: In early work , Rutherford discovered the concept of radioactive half-life, the radioactive element radon, and classified three types of radiations: alpha, beta and gamma radiation .

Solution is here: Rutherford discovered the radioactive half-life, the chemical element radon, and the three parts of radiation which he named Alpha, Beta, and Gamma .

Explanation: The output sentence is a simplified version of the input sentence.

Now, solve this: The higher the specific impulse , the less propellant is needed to produce a given thrust for a given time and the more efficient the propellant is .
Solution:
So , a fuel is more efficient if the specific impulse is higher .